mirror of
https://github.com/open-policy-agent/opa.git
synced 2026-08-12 19:32:48 -06:00
Torin Sandall
e2297a7833
- Updated source code layout to use standard Go project structure. - Makefile for build and test execution. - Glide for dependency management. - Integrated spf13/cobra for command line entry point. - Added docs on release and development process.
1613 lines
37 KiB
Go
1613 lines
37 KiB
Go
// Command json parses JSON as defined by [1].
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//
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// BUGS: the escaped forward solidus (`\/`) is not currently handled for strings.
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//
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// TODO: check if JSON's numbers are a subset of Go's numbers, since we are
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// assuming they are. Currently representing all numbers as float64.
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// TODO: think about relaxing a Dictionary to allow numeric keys, as they are common in practice.
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// [1]: http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-404.pdf
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package jsonlog
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import (
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"bytes"
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"errors"
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"fmt"
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"io"
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"io/ioutil"
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"os"
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"strconv"
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"strings"
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"unicode"
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"unicode/utf8"
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)
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func toIfaceSlice(v interface{}) []interface{} {
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if v == nil {
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return nil
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}
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return v.([]interface{})
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}
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var g = &grammar{
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rules: []*rule{
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{
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name: "Prog",
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pos: position{line: 20, col: 1, offset: 612},
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expr: &actionExpr{
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pos: position{line: 20, col: 9, offset: 620},
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run: (*parser).callonProg1,
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expr: &seqExpr{
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pos: position{line: 20, col: 9, offset: 620},
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exprs: []interface{}{
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&ruleRefExpr{
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pos: position{line: 20, col: 9, offset: 620},
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name: "_",
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},
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&labeledExpr{
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pos: position{line: 20, col: 11, offset: 622},
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label: "vals",
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expr: &oneOrMoreExpr{
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pos: position{line: 20, col: 16, offset: 627},
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expr: &ruleRefExpr{
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pos: position{line: 20, col: 16, offset: 627},
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name: "Term",
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},
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},
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},
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&ruleRefExpr{
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pos: position{line: 20, col: 22, offset: 633},
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name: "EOF",
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},
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},
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},
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},
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},
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{
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name: "Term",
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pos: position{line: 27, col: 1, offset: 749},
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expr: &actionExpr{
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pos: position{line: 27, col: 9, offset: 757},
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run: (*parser).callonTerm1,
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expr: &seqExpr{
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pos: position{line: 27, col: 9, offset: 757},
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exprs: []interface{}{
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&labeledExpr{
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pos: position{line: 27, col: 9, offset: 757},
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label: "val",
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expr: &choiceExpr{
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pos: position{line: 27, col: 15, offset: 763},
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alternatives: []interface{}{
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&ruleRefExpr{
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pos: position{line: 27, col: 15, offset: 763},
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name: "Dictionary",
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},
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&ruleRefExpr{
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pos: position{line: 27, col: 28, offset: 776},
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name: "Array",
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},
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&ruleRefExpr{
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pos: position{line: 27, col: 36, offset: 784},
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name: "Number",
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},
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&ruleRefExpr{
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pos: position{line: 27, col: 45, offset: 793},
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name: "String",
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},
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&ruleRefExpr{
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pos: position{line: 27, col: 54, offset: 802},
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name: "Bool",
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},
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&ruleRefExpr{
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pos: position{line: 27, col: 61, offset: 809},
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name: "Null",
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},
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},
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},
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},
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&ruleRefExpr{
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pos: position{line: 27, col: 68, offset: 816},
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name: "_",
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},
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},
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},
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},
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},
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{
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name: "Dictionary",
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pos: position{line: 31, col: 1, offset: 843},
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expr: &actionExpr{
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pos: position{line: 31, col: 15, offset: 857},
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run: (*parser).callonDictionary1,
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expr: &seqExpr{
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pos: position{line: 31, col: 15, offset: 857},
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exprs: []interface{}{
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&litMatcher{
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pos: position{line: 31, col: 15, offset: 857},
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val: "{",
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ignoreCase: false,
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},
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&ruleRefExpr{
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pos: position{line: 31, col: 19, offset: 861},
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name: "_",
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},
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&labeledExpr{
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pos: position{line: 31, col: 21, offset: 863},
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label: "vals",
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expr: &zeroOrOneExpr{
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pos: position{line: 31, col: 26, offset: 868},
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expr: &seqExpr{
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pos: position{line: 31, col: 28, offset: 870},
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exprs: []interface{}{
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&ruleRefExpr{
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pos: position{line: 31, col: 28, offset: 870},
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name: "String",
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},
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&ruleRefExpr{
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pos: position{line: 31, col: 35, offset: 877},
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name: "_",
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},
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&litMatcher{
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pos: position{line: 31, col: 37, offset: 879},
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val: ":",
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ignoreCase: false,
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},
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&ruleRefExpr{
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pos: position{line: 31, col: 41, offset: 883},
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name: "_",
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},
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&ruleRefExpr{
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pos: position{line: 31, col: 43, offset: 885},
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name: "Term",
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},
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&zeroOrMoreExpr{
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pos: position{line: 31, col: 48, offset: 890},
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expr: &seqExpr{
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pos: position{line: 31, col: 50, offset: 892},
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exprs: []interface{}{
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&litMatcher{
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pos: position{line: 31, col: 50, offset: 892},
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val: ",",
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ignoreCase: false,
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},
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&ruleRefExpr{
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pos: position{line: 31, col: 54, offset: 896},
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name: "_",
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},
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&ruleRefExpr{
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pos: position{line: 31, col: 56, offset: 898},
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name: "String",
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},
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&ruleRefExpr{
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pos: position{line: 31, col: 63, offset: 905},
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name: "_",
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},
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&litMatcher{
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pos: position{line: 31, col: 65, offset: 907},
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val: ":",
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ignoreCase: false,
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},
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&ruleRefExpr{
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pos: position{line: 31, col: 69, offset: 911},
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name: "_",
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},
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&ruleRefExpr{
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pos: position{line: 31, col: 71, offset: 913},
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name: "Term",
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},
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},
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},
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},
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},
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},
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},
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},
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&litMatcher{
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pos: position{line: 31, col: 82, offset: 924},
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val: "}",
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ignoreCase: false,
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},
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},
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},
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},
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},
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{
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name: "Array",
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pos: position{line: 49, col: 1, offset: 1591},
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expr: &actionExpr{
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pos: position{line: 49, col: 10, offset: 1600},
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run: (*parser).callonArray1,
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expr: &seqExpr{
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pos: position{line: 49, col: 10, offset: 1600},
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exprs: []interface{}{
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&litMatcher{
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pos: position{line: 49, col: 10, offset: 1600},
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val: "[",
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ignoreCase: false,
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},
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&ruleRefExpr{
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pos: position{line: 49, col: 14, offset: 1604},
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name: "_",
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},
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&labeledExpr{
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pos: position{line: 49, col: 16, offset: 1606},
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label: "vals",
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expr: &zeroOrOneExpr{
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pos: position{line: 49, col: 21, offset: 1611},
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expr: &seqExpr{
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pos: position{line: 49, col: 23, offset: 1613},
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exprs: []interface{}{
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&ruleRefExpr{
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pos: position{line: 49, col: 23, offset: 1613},
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name: "Value",
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},
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&zeroOrMoreExpr{
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pos: position{line: 49, col: 29, offset: 1619},
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expr: &seqExpr{
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pos: position{line: 49, col: 31, offset: 1621},
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exprs: []interface{}{
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&litMatcher{
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pos: position{line: 49, col: 31, offset: 1621},
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val: ",",
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ignoreCase: false,
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},
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&ruleRefExpr{
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pos: position{line: 49, col: 35, offset: 1625},
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name: "_",
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},
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&ruleRefExpr{
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pos: position{line: 49, col: 37, offset: 1627},
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name: "Value",
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},
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},
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},
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},
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},
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},
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},
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},
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&litMatcher{
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pos: position{line: 49, col: 49, offset: 1639},
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val: "]",
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ignoreCase: false,
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},
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},
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},
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},
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},
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{
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name: "Number",
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pos: position{line: 64, col: 1, offset: 2067},
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expr: &actionExpr{
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pos: position{line: 64, col: 11, offset: 2077},
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run: (*parser).callonNumber1,
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expr: &seqExpr{
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pos: position{line: 64, col: 11, offset: 2077},
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exprs: []interface{}{
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&zeroOrOneExpr{
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pos: position{line: 64, col: 11, offset: 2077},
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expr: &litMatcher{
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pos: position{line: 64, col: 11, offset: 2077},
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val: "-",
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ignoreCase: false,
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},
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},
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&ruleRefExpr{
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pos: position{line: 64, col: 16, offset: 2082},
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name: "Integer",
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},
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&zeroOrOneExpr{
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pos: position{line: 64, col: 24, offset: 2090},
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expr: &seqExpr{
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pos: position{line: 64, col: 26, offset: 2092},
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exprs: []interface{}{
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&litMatcher{
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pos: position{line: 64, col: 26, offset: 2092},
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val: ".",
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ignoreCase: false,
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},
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&oneOrMoreExpr{
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pos: position{line: 64, col: 30, offset: 2096},
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expr: &ruleRefExpr{
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pos: position{line: 64, col: 30, offset: 2096},
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name: "DecimalDigit",
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},
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},
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},
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},
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},
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&zeroOrOneExpr{
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pos: position{line: 64, col: 47, offset: 2113},
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expr: &ruleRefExpr{
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pos: position{line: 64, col: 47, offset: 2113},
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name: "Exponent",
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},
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},
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},
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},
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},
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},
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{
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name: "Integer",
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pos: position{line: 72, col: 1, offset: 2352},
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expr: &choiceExpr{
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pos: position{line: 72, col: 12, offset: 2363},
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alternatives: []interface{}{
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&litMatcher{
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pos: position{line: 72, col: 12, offset: 2363},
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val: "0",
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ignoreCase: false,
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},
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&seqExpr{
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pos: position{line: 72, col: 18, offset: 2369},
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exprs: []interface{}{
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&ruleRefExpr{
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pos: position{line: 72, col: 18, offset: 2369},
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name: "NonZeroDecimalDigit",
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},
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&zeroOrMoreExpr{
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pos: position{line: 72, col: 38, offset: 2389},
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expr: &ruleRefExpr{
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pos: position{line: 72, col: 38, offset: 2389},
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name: "DecimalDigit",
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},
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},
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},
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},
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},
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},
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},
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{
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name: "Exponent",
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pos: position{line: 74, col: 1, offset: 2404},
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expr: &seqExpr{
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pos: position{line: 74, col: 13, offset: 2416},
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exprs: []interface{}{
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&litMatcher{
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pos: position{line: 74, col: 13, offset: 2416},
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val: "e",
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ignoreCase: true,
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},
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&zeroOrOneExpr{
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pos: position{line: 74, col: 18, offset: 2421},
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expr: &charClassMatcher{
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pos: position{line: 74, col: 18, offset: 2421},
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val: "[+-]",
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chars: []rune{'+', '-'},
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ignoreCase: false,
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inverted: false,
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},
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},
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&oneOrMoreExpr{
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pos: position{line: 74, col: 24, offset: 2427},
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expr: &ruleRefExpr{
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pos: position{line: 74, col: 24, offset: 2427},
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name: "DecimalDigit",
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},
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},
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},
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},
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},
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{
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name: "String",
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pos: position{line: 76, col: 1, offset: 2442},
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expr: &actionExpr{
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pos: position{line: 76, col: 11, offset: 2452},
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run: (*parser).callonString1,
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expr: &seqExpr{
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pos: position{line: 76, col: 11, offset: 2452},
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exprs: []interface{}{
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&litMatcher{
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pos: position{line: 76, col: 11, offset: 2452},
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val: "\"",
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ignoreCase: false,
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},
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&zeroOrMoreExpr{
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pos: position{line: 76, col: 15, offset: 2456},
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expr: &choiceExpr{
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pos: position{line: 76, col: 17, offset: 2458},
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alternatives: []interface{}{
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&seqExpr{
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pos: position{line: 76, col: 17, offset: 2458},
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exprs: []interface{}{
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¬Expr{
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pos: position{line: 76, col: 17, offset: 2458},
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expr: &ruleRefExpr{
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pos: position{line: 76, col: 18, offset: 2459},
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name: "EscapedChar",
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},
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},
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&anyMatcher{
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line: 76, col: 30, offset: 2471,
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},
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},
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},
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&seqExpr{
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pos: position{line: 76, col: 34, offset: 2475},
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exprs: []interface{}{
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&litMatcher{
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pos: position{line: 76, col: 34, offset: 2475},
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val: "\\",
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ignoreCase: false,
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},
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&ruleRefExpr{
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pos: position{line: 76, col: 39, offset: 2480},
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name: "EscapeSequence",
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},
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},
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},
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},
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},
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},
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&litMatcher{
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pos: position{line: 76, col: 57, offset: 2498},
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val: "\"",
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ignoreCase: false,
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},
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},
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},
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},
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},
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{
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name: "EscapedChar",
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pos: position{line: 84, col: 1, offset: 2764},
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|
expr: &charClassMatcher{
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|
pos: position{line: 84, col: 16, offset: 2779},
|
|
val: "[\\x00-\\x1f\"\\\\]",
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|
chars: []rune{'"', '\\'},
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ranges: []rune{'\x00', '\x1f'},
|
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ignoreCase: false,
|
|
inverted: false,
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|
},
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|
},
|
|
{
|
|
name: "EscapeSequence",
|
|
pos: position{line: 86, col: 1, offset: 2795},
|
|
expr: &choiceExpr{
|
|
pos: position{line: 86, col: 19, offset: 2813},
|
|
alternatives: []interface{}{
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|
&ruleRefExpr{
|
|
pos: position{line: 86, col: 19, offset: 2813},
|
|
name: "SingleCharEscape",
|
|
},
|
|
&ruleRefExpr{
|
|
pos: position{line: 86, col: 38, offset: 2832},
|
|
name: "UnicodeEscape",
|
|
},
|
|
},
|
|
},
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|
},
|
|
{
|
|
name: "SingleCharEscape",
|
|
pos: position{line: 88, col: 1, offset: 2847},
|
|
expr: &charClassMatcher{
|
|
pos: position{line: 88, col: 21, offset: 2867},
|
|
val: "[\"\\\\/bfnrt]",
|
|
chars: []rune{'"', '\\', '/', 'b', 'f', 'n', 'r', 't'},
|
|
ignoreCase: false,
|
|
inverted: false,
|
|
},
|
|
},
|
|
{
|
|
name: "UnicodeEscape",
|
|
pos: position{line: 90, col: 1, offset: 2880},
|
|
expr: &seqExpr{
|
|
pos: position{line: 90, col: 18, offset: 2897},
|
|
exprs: []interface{}{
|
|
&litMatcher{
|
|
pos: position{line: 90, col: 18, offset: 2897},
|
|
val: "u",
|
|
ignoreCase: false,
|
|
},
|
|
&ruleRefExpr{
|
|
pos: position{line: 90, col: 22, offset: 2901},
|
|
name: "HexDigit",
|
|
},
|
|
&ruleRefExpr{
|
|
pos: position{line: 90, col: 31, offset: 2910},
|
|
name: "HexDigit",
|
|
},
|
|
&ruleRefExpr{
|
|
pos: position{line: 90, col: 40, offset: 2919},
|
|
name: "HexDigit",
|
|
},
|
|
&ruleRefExpr{
|
|
pos: position{line: 90, col: 49, offset: 2928},
|
|
name: "HexDigit",
|
|
},
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|
},
|
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},
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|
},
|
|
{
|
|
name: "DecimalDigit",
|
|
pos: position{line: 92, col: 1, offset: 2938},
|
|
expr: &charClassMatcher{
|
|
pos: position{line: 92, col: 17, offset: 2954},
|
|
val: "[0-9]",
|
|
ranges: []rune{'0', '9'},
|
|
ignoreCase: false,
|
|
inverted: false,
|
|
},
|
|
},
|
|
{
|
|
name: "NonZeroDecimalDigit",
|
|
pos: position{line: 94, col: 1, offset: 2961},
|
|
expr: &charClassMatcher{
|
|
pos: position{line: 94, col: 24, offset: 2984},
|
|
val: "[1-9]",
|
|
ranges: []rune{'1', '9'},
|
|
ignoreCase: false,
|
|
inverted: false,
|
|
},
|
|
},
|
|
{
|
|
name: "HexDigit",
|
|
pos: position{line: 96, col: 1, offset: 2991},
|
|
expr: &charClassMatcher{
|
|
pos: position{line: 96, col: 13, offset: 3003},
|
|
val: "[0-9a-f]i",
|
|
ranges: []rune{'0', '9', 'a', 'f'},
|
|
ignoreCase: true,
|
|
inverted: false,
|
|
},
|
|
},
|
|
{
|
|
name: "Bool",
|
|
pos: position{line: 98, col: 1, offset: 3014},
|
|
expr: &choiceExpr{
|
|
pos: position{line: 98, col: 9, offset: 3022},
|
|
alternatives: []interface{}{
|
|
&actionExpr{
|
|
pos: position{line: 98, col: 9, offset: 3022},
|
|
run: (*parser).callonBool2,
|
|
expr: &litMatcher{
|
|
pos: position{line: 98, col: 9, offset: 3022},
|
|
val: "true",
|
|
ignoreCase: false,
|
|
},
|
|
},
|
|
&actionExpr{
|
|
pos: position{line: 101, col: 5, offset: 3133},
|
|
run: (*parser).callonBool4,
|
|
expr: &litMatcher{
|
|
pos: position{line: 101, col: 5, offset: 3133},
|
|
val: "false",
|
|
ignoreCase: false,
|
|
},
|
|
},
|
|
},
|
|
},
|
|
},
|
|
{
|
|
name: "Null",
|
|
pos: position{line: 106, col: 1, offset: 3246},
|
|
expr: &actionExpr{
|
|
pos: position{line: 106, col: 9, offset: 3254},
|
|
run: (*parser).callonNull1,
|
|
expr: &litMatcher{
|
|
pos: position{line: 106, col: 9, offset: 3254},
|
|
val: "null",
|
|
ignoreCase: false,
|
|
},
|
|
},
|
|
},
|
|
{
|
|
name: "_",
|
|
displayName: "\"whitespace\"",
|
|
pos: position{line: 111, col: 1, offset: 3358},
|
|
expr: &zeroOrMoreExpr{
|
|
pos: position{line: 111, col: 19, offset: 3376},
|
|
expr: &charClassMatcher{
|
|
pos: position{line: 111, col: 19, offset: 3376},
|
|
val: "[ \\t\\r\\n]",
|
|
chars: []rune{' ', '\t', '\r', '\n'},
|
|
ignoreCase: false,
|
|
inverted: false,
|
|
},
|
|
},
|
|
},
|
|
{
|
|
name: "EOF",
|
|
pos: position{line: 113, col: 1, offset: 3388},
|
|
expr: ¬Expr{
|
|
pos: position{line: 113, col: 8, offset: 3395},
|
|
expr: &anyMatcher{
|
|
line: 113, col: 9, offset: 3396,
|
|
},
|
|
},
|
|
},
|
|
},
|
|
}
|
|
|
|
func (c *current) onProg1(vals interface{}) (interface{}, error) {
|
|
if vals == nil {
|
|
return make([]interface{}, 0), nil
|
|
}
|
|
return vals.([]interface{}), nil
|
|
}
|
|
|
|
func (p *parser) callonProg1() (interface{}, error) {
|
|
stack := p.vstack[len(p.vstack)-1]
|
|
_ = stack
|
|
return p.cur.onProg1(stack["vals"])
|
|
}
|
|
|
|
func (c *current) onTerm1(val interface{}) (interface{}, error) {
|
|
return val, nil
|
|
}
|
|
|
|
func (p *parser) callonTerm1() (interface{}, error) {
|
|
stack := p.vstack[len(p.vstack)-1]
|
|
_ = stack
|
|
return p.cur.onTerm1(stack["val"])
|
|
}
|
|
|
|
func (c *current) onDictionary1(vals interface{}) (interface{}, error) {
|
|
valsSl := toIfaceSlice(vals)
|
|
if len(valsSl) == 0 {
|
|
return NewTerm([]*Term{}, DICTIONARY, c.text, "", c.pos.line, c.pos.col), nil
|
|
}
|
|
restSl := toIfaceSlice(valsSl[5])
|
|
// Storing dictionary arguments as a set of KeyValue pairs since we may not be
|
|
// able to evaluate the keys (e.g. the key may be a variable)
|
|
res := NewKeyValueSet()
|
|
res.Add(NewKeyValue(valsSl[0].(*Term), valsSl[4].(*Term)))
|
|
for _, v := range restSl {
|
|
vSl := toIfaceSlice(v)
|
|
res.Add(NewKeyValue(vSl[2].(*Term), vSl[6].(*Term)))
|
|
}
|
|
t := NewTerm(res, DICTIONARY, c.text, "", c.pos.line, c.pos.col)
|
|
return t, nil //res, nil
|
|
}
|
|
|
|
func (p *parser) callonDictionary1() (interface{}, error) {
|
|
stack := p.vstack[len(p.vstack)-1]
|
|
_ = stack
|
|
return p.cur.onDictionary1(stack["vals"])
|
|
}
|
|
|
|
func (c *current) onArray1(vals interface{}) (interface{}, error) {
|
|
valsSl := toIfaceSlice(vals)
|
|
if len(valsSl) == 0 {
|
|
return NewTerm([]*Term{}, ARRAY, c.text, "", c.pos.line, c.pos.col), nil
|
|
}
|
|
restSl := toIfaceSlice(valsSl[1])
|
|
res := make([]*Term, 1+len(valsSl))
|
|
for i, v := range restSl {
|
|
vSl := toIfaceSlice(v)
|
|
res[i] = vSl[2].(*Term)
|
|
}
|
|
t := NewTerm(res, ARRAY, c.text, "", c.pos.line, c.pos.col)
|
|
return t, nil //res, nil
|
|
}
|
|
|
|
func (p *parser) callonArray1() (interface{}, error) {
|
|
stack := p.vstack[len(p.vstack)-1]
|
|
_ = stack
|
|
return p.cur.onArray1(stack["vals"])
|
|
}
|
|
|
|
func (c *current) onNumber1() (interface{}, error) {
|
|
// JSON numbers have the same syntax as Go's, and are parseable using
|
|
// strconv.
|
|
v, err := strconv.ParseFloat(string(c.text), 64)
|
|
t := NewTerm(v, NUMBER, c.text, "", c.pos.line, c.pos.col)
|
|
return t, err
|
|
}
|
|
|
|
func (p *parser) callonNumber1() (interface{}, error) {
|
|
stack := p.vstack[len(p.vstack)-1]
|
|
_ = stack
|
|
return p.cur.onNumber1()
|
|
}
|
|
|
|
func (c *current) onString1() (interface{}, error) {
|
|
// TODO : the forward slash (solidus) is not a valid escape in Go, it will
|
|
// fail if there's one in the string
|
|
v, err := strconv.Unquote(string(c.text))
|
|
t := NewTerm(v, STRING, c.text, "", c.pos.line, c.pos.col)
|
|
return t, err // v, err
|
|
}
|
|
|
|
func (p *parser) callonString1() (interface{}, error) {
|
|
stack := p.vstack[len(p.vstack)-1]
|
|
_ = stack
|
|
return p.cur.onString1()
|
|
}
|
|
|
|
func (c *current) onBool2() (interface{}, error) {
|
|
t := NewTerm(true, BOOLEAN, c.text, "", c.pos.line, c.pos.col)
|
|
return t, nil // true, nil
|
|
}
|
|
|
|
func (p *parser) callonBool2() (interface{}, error) {
|
|
stack := p.vstack[len(p.vstack)-1]
|
|
_ = stack
|
|
return p.cur.onBool2()
|
|
}
|
|
|
|
func (c *current) onBool4() (interface{}, error) {
|
|
t := NewTerm(false, BOOLEAN, c.text, "", c.pos.line, c.pos.col)
|
|
return t, nil // false, nil
|
|
}
|
|
|
|
func (p *parser) callonBool4() (interface{}, error) {
|
|
stack := p.vstack[len(p.vstack)-1]
|
|
_ = stack
|
|
return p.cur.onBool4()
|
|
}
|
|
|
|
func (c *current) onNull1() (interface{}, error) {
|
|
t := NewTerm(nil, NULL, c.text, "", c.pos.line, c.pos.col)
|
|
return t, nil //nil, nil
|
|
}
|
|
|
|
func (p *parser) callonNull1() (interface{}, error) {
|
|
stack := p.vstack[len(p.vstack)-1]
|
|
_ = stack
|
|
return p.cur.onNull1()
|
|
}
|
|
|
|
var (
|
|
// errNoRule is returned when the grammar to parse has no rule.
|
|
errNoRule = errors.New("grammar has no rule")
|
|
|
|
// errInvalidEncoding is returned when the source is not properly
|
|
// utf8-encoded.
|
|
errInvalidEncoding = errors.New("invalid encoding")
|
|
|
|
// errNoMatch is returned if no match could be found.
|
|
errNoMatch = errors.New("no match found")
|
|
)
|
|
|
|
// Option is a function that can set an option on the parser. It returns
|
|
// the previous setting as an Option.
|
|
type Option func(*parser) Option
|
|
|
|
// Debug creates an Option to set the debug flag to b. When set to true,
|
|
// debugging information is printed to stdout while parsing.
|
|
//
|
|
// The default is false.
|
|
func Debug(b bool) Option {
|
|
return func(p *parser) Option {
|
|
old := p.debug
|
|
p.debug = b
|
|
return Debug(old)
|
|
}
|
|
}
|
|
|
|
// Memoize creates an Option to set the memoize flag to b. When set to true,
|
|
// the parser will cache all results so each expression is evaluated only
|
|
// once. This guarantees linear parsing time even for pathological cases,
|
|
// at the expense of more memory and slower times for typical cases.
|
|
//
|
|
// The default is false.
|
|
func Memoize(b bool) Option {
|
|
return func(p *parser) Option {
|
|
old := p.memoize
|
|
p.memoize = b
|
|
return Memoize(old)
|
|
}
|
|
}
|
|
|
|
// Recover creates an Option to set the recover flag to b. When set to
|
|
// true, this causes the parser to recover from panics and convert it
|
|
// to an error. Setting it to false can be useful while debugging to
|
|
// access the full stack trace.
|
|
//
|
|
// The default is true.
|
|
func Recover(b bool) Option {
|
|
return func(p *parser) Option {
|
|
old := p.recover
|
|
p.recover = b
|
|
return Recover(old)
|
|
}
|
|
}
|
|
|
|
// ParseFile parses the file identified by filename.
|
|
func ParseFile(filename string, opts ...Option) (interface{}, error) {
|
|
f, err := os.Open(filename)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
defer f.Close()
|
|
return ParseReader(filename, f, opts...)
|
|
}
|
|
|
|
// ParseReader parses the data from r using filename as information in the
|
|
// error messages.
|
|
func ParseReader(filename string, r io.Reader, opts ...Option) (interface{}, error) {
|
|
b, err := ioutil.ReadAll(r)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return Parse(filename, b, opts...)
|
|
}
|
|
|
|
// Parse parses the data from b using filename as information in the
|
|
// error messages.
|
|
func Parse(filename string, b []byte, opts ...Option) (interface{}, error) {
|
|
return newParser(filename, b, opts...).parse(g)
|
|
}
|
|
|
|
// position records a position in the text.
|
|
type position struct {
|
|
line, col, offset int
|
|
}
|
|
|
|
func (p position) String() string {
|
|
return fmt.Sprintf("%d:%d [%d]", p.line, p.col, p.offset)
|
|
}
|
|
|
|
// savepoint stores all state required to go back to this point in the
|
|
// parser.
|
|
type savepoint struct {
|
|
position
|
|
rn rune
|
|
w int
|
|
}
|
|
|
|
type current struct {
|
|
pos position // start position of the match
|
|
text []byte // raw text of the match
|
|
}
|
|
|
|
// the AST types...
|
|
|
|
type grammar struct {
|
|
pos position
|
|
rules []*rule
|
|
}
|
|
|
|
type rule struct {
|
|
pos position
|
|
name string
|
|
displayName string
|
|
expr interface{}
|
|
}
|
|
|
|
type choiceExpr struct {
|
|
pos position
|
|
alternatives []interface{}
|
|
}
|
|
|
|
type actionExpr struct {
|
|
pos position
|
|
expr interface{}
|
|
run func(*parser) (interface{}, error)
|
|
}
|
|
|
|
type seqExpr struct {
|
|
pos position
|
|
exprs []interface{}
|
|
}
|
|
|
|
type labeledExpr struct {
|
|
pos position
|
|
label string
|
|
expr interface{}
|
|
}
|
|
|
|
type expr struct {
|
|
pos position
|
|
expr interface{}
|
|
}
|
|
|
|
type andExpr expr
|
|
type notExpr expr
|
|
type zeroOrOneExpr expr
|
|
type zeroOrMoreExpr expr
|
|
type oneOrMoreExpr expr
|
|
|
|
type ruleRefExpr struct {
|
|
pos position
|
|
name string
|
|
}
|
|
|
|
type andCodeExpr struct {
|
|
pos position
|
|
run func(*parser) (bool, error)
|
|
}
|
|
|
|
type notCodeExpr struct {
|
|
pos position
|
|
run func(*parser) (bool, error)
|
|
}
|
|
|
|
type litMatcher struct {
|
|
pos position
|
|
val string
|
|
ignoreCase bool
|
|
}
|
|
|
|
type charClassMatcher struct {
|
|
pos position
|
|
val string
|
|
chars []rune
|
|
ranges []rune
|
|
classes []*unicode.RangeTable
|
|
ignoreCase bool
|
|
inverted bool
|
|
}
|
|
|
|
type anyMatcher position
|
|
|
|
// errList cumulates the errors found by the parser.
|
|
type errList []error
|
|
|
|
func (e *errList) add(err error) {
|
|
*e = append(*e, err)
|
|
}
|
|
|
|
func (e errList) err() error {
|
|
if len(e) == 0 {
|
|
return nil
|
|
}
|
|
e.dedupe()
|
|
return e
|
|
}
|
|
|
|
func (e *errList) dedupe() {
|
|
var cleaned []error
|
|
set := make(map[string]bool)
|
|
for _, err := range *e {
|
|
if msg := err.Error(); !set[msg] {
|
|
set[msg] = true
|
|
cleaned = append(cleaned, err)
|
|
}
|
|
}
|
|
*e = cleaned
|
|
}
|
|
|
|
func (e errList) Error() string {
|
|
switch len(e) {
|
|
case 0:
|
|
return ""
|
|
case 1:
|
|
return e[0].Error()
|
|
default:
|
|
var buf bytes.Buffer
|
|
|
|
for i, err := range e {
|
|
if i > 0 {
|
|
buf.WriteRune('\n')
|
|
}
|
|
buf.WriteString(err.Error())
|
|
}
|
|
return buf.String()
|
|
}
|
|
}
|
|
|
|
// parserError wraps an error with a prefix indicating the rule in which
|
|
// the error occurred. The original error is stored in the Inner field.
|
|
type parserError struct {
|
|
Inner error
|
|
pos position
|
|
prefix string
|
|
}
|
|
|
|
// Error returns the error message.
|
|
func (p *parserError) Error() string {
|
|
return p.prefix + ": " + p.Inner.Error()
|
|
}
|
|
|
|
// newParser creates a parser with the specified input source and options.
|
|
func newParser(filename string, b []byte, opts ...Option) *parser {
|
|
p := &parser{
|
|
filename: filename,
|
|
errs: new(errList),
|
|
data: b,
|
|
pt: savepoint{position: position{line: 1}},
|
|
recover: true,
|
|
}
|
|
p.setOptions(opts)
|
|
return p
|
|
}
|
|
|
|
// setOptions applies the options to the parser.
|
|
func (p *parser) setOptions(opts []Option) {
|
|
for _, opt := range opts {
|
|
opt(p)
|
|
}
|
|
}
|
|
|
|
type resultTuple struct {
|
|
v interface{}
|
|
b bool
|
|
end savepoint
|
|
}
|
|
|
|
type parser struct {
|
|
filename string
|
|
pt savepoint
|
|
cur current
|
|
|
|
data []byte
|
|
errs *errList
|
|
|
|
recover bool
|
|
debug bool
|
|
depth int
|
|
|
|
memoize bool
|
|
// memoization table for the packrat algorithm:
|
|
// map[offset in source] map[expression or rule] {value, match}
|
|
memo map[int]map[interface{}]resultTuple
|
|
|
|
// rules table, maps the rule identifier to the rule node
|
|
rules map[string]*rule
|
|
// variables stack, map of label to value
|
|
vstack []map[string]interface{}
|
|
// rule stack, allows identification of the current rule in errors
|
|
rstack []*rule
|
|
|
|
// stats
|
|
exprCnt int
|
|
}
|
|
|
|
// push a variable set on the vstack.
|
|
func (p *parser) pushV() {
|
|
if cap(p.vstack) == len(p.vstack) {
|
|
// create new empty slot in the stack
|
|
p.vstack = append(p.vstack, nil)
|
|
} else {
|
|
// slice to 1 more
|
|
p.vstack = p.vstack[:len(p.vstack)+1]
|
|
}
|
|
|
|
// get the last args set
|
|
m := p.vstack[len(p.vstack)-1]
|
|
if m != nil && len(m) == 0 {
|
|
// empty map, all good
|
|
return
|
|
}
|
|
|
|
m = make(map[string]interface{})
|
|
p.vstack[len(p.vstack)-1] = m
|
|
}
|
|
|
|
// pop a variable set from the vstack.
|
|
func (p *parser) popV() {
|
|
// if the map is not empty, clear it
|
|
m := p.vstack[len(p.vstack)-1]
|
|
if len(m) > 0 {
|
|
// GC that map
|
|
p.vstack[len(p.vstack)-1] = nil
|
|
}
|
|
p.vstack = p.vstack[:len(p.vstack)-1]
|
|
}
|
|
|
|
func (p *parser) print(prefix, s string) string {
|
|
if !p.debug {
|
|
return s
|
|
}
|
|
|
|
fmt.Printf("%s %d:%d:%d: %s [%#U]\n",
|
|
prefix, p.pt.line, p.pt.col, p.pt.offset, s, p.pt.rn)
|
|
return s
|
|
}
|
|
|
|
func (p *parser) in(s string) string {
|
|
p.depth++
|
|
return p.print(strings.Repeat(" ", p.depth)+">", s)
|
|
}
|
|
|
|
func (p *parser) out(s string) string {
|
|
p.depth--
|
|
return p.print(strings.Repeat(" ", p.depth)+"<", s)
|
|
}
|
|
|
|
func (p *parser) addErr(err error) {
|
|
p.addErrAt(err, p.pt.position)
|
|
}
|
|
|
|
func (p *parser) addErrAt(err error, pos position) {
|
|
var buf bytes.Buffer
|
|
if p.filename != "" {
|
|
buf.WriteString(p.filename)
|
|
}
|
|
if buf.Len() > 0 {
|
|
buf.WriteString(":")
|
|
}
|
|
buf.WriteString(fmt.Sprintf("%d:%d (%d)", pos.line, pos.col, pos.offset))
|
|
if len(p.rstack) > 0 {
|
|
if buf.Len() > 0 {
|
|
buf.WriteString(": ")
|
|
}
|
|
rule := p.rstack[len(p.rstack)-1]
|
|
if rule.displayName != "" {
|
|
buf.WriteString("rule " + rule.displayName)
|
|
} else {
|
|
buf.WriteString("rule " + rule.name)
|
|
}
|
|
}
|
|
pe := &parserError{Inner: err, prefix: buf.String()}
|
|
p.errs.add(pe)
|
|
}
|
|
|
|
// read advances the parser to the next rune.
|
|
func (p *parser) read() {
|
|
p.pt.offset += p.pt.w
|
|
rn, n := utf8.DecodeRune(p.data[p.pt.offset:])
|
|
p.pt.rn = rn
|
|
p.pt.w = n
|
|
p.pt.col++
|
|
if rn == '\n' {
|
|
p.pt.line++
|
|
p.pt.col = 0
|
|
}
|
|
|
|
if rn == utf8.RuneError {
|
|
if n > 0 {
|
|
p.addErr(errInvalidEncoding)
|
|
}
|
|
}
|
|
}
|
|
|
|
// restore parser position to the savepoint pt.
|
|
func (p *parser) restore(pt savepoint) {
|
|
if p.debug {
|
|
defer p.out(p.in("restore"))
|
|
}
|
|
if pt.offset == p.pt.offset {
|
|
return
|
|
}
|
|
p.pt = pt
|
|
}
|
|
|
|
// get the slice of bytes from the savepoint start to the current position.
|
|
func (p *parser) sliceFrom(start savepoint) []byte {
|
|
return p.data[start.position.offset:p.pt.position.offset]
|
|
}
|
|
|
|
func (p *parser) getMemoized(node interface{}) (resultTuple, bool) {
|
|
if len(p.memo) == 0 {
|
|
return resultTuple{}, false
|
|
}
|
|
m := p.memo[p.pt.offset]
|
|
if len(m) == 0 {
|
|
return resultTuple{}, false
|
|
}
|
|
res, ok := m[node]
|
|
return res, ok
|
|
}
|
|
|
|
func (p *parser) setMemoized(pt savepoint, node interface{}, tuple resultTuple) {
|
|
if p.memo == nil {
|
|
p.memo = make(map[int]map[interface{}]resultTuple)
|
|
}
|
|
m := p.memo[pt.offset]
|
|
if m == nil {
|
|
m = make(map[interface{}]resultTuple)
|
|
p.memo[pt.offset] = m
|
|
}
|
|
m[node] = tuple
|
|
}
|
|
|
|
func (p *parser) buildRulesTable(g *grammar) {
|
|
p.rules = make(map[string]*rule, len(g.rules))
|
|
for _, r := range g.rules {
|
|
p.rules[r.name] = r
|
|
}
|
|
}
|
|
|
|
func (p *parser) parse(g *grammar) (val interface{}, err error) {
|
|
if len(g.rules) == 0 {
|
|
p.addErr(errNoRule)
|
|
return nil, p.errs.err()
|
|
}
|
|
|
|
// TODO : not super critical but this could be generated
|
|
p.buildRulesTable(g)
|
|
|
|
if p.recover {
|
|
// panic can be used in action code to stop parsing immediately
|
|
// and return the panic as an error.
|
|
defer func() {
|
|
if e := recover(); e != nil {
|
|
if p.debug {
|
|
defer p.out(p.in("panic handler"))
|
|
}
|
|
val = nil
|
|
switch e := e.(type) {
|
|
case error:
|
|
p.addErr(e)
|
|
default:
|
|
p.addErr(fmt.Errorf("%v", e))
|
|
}
|
|
err = p.errs.err()
|
|
}
|
|
}()
|
|
}
|
|
|
|
// start rule is rule [0]
|
|
p.read() // advance to first rune
|
|
val, ok := p.parseRule(g.rules[0])
|
|
if !ok {
|
|
if len(*p.errs) == 0 {
|
|
// make sure this doesn't go out silently
|
|
p.addErr(errNoMatch)
|
|
}
|
|
return nil, p.errs.err()
|
|
}
|
|
return val, p.errs.err()
|
|
}
|
|
|
|
func (p *parser) parseRule(rule *rule) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseRule " + rule.name))
|
|
}
|
|
|
|
if p.memoize {
|
|
res, ok := p.getMemoized(rule)
|
|
if ok {
|
|
p.restore(res.end)
|
|
return res.v, res.b
|
|
}
|
|
}
|
|
|
|
start := p.pt
|
|
p.rstack = append(p.rstack, rule)
|
|
p.pushV()
|
|
val, ok := p.parseExpr(rule.expr)
|
|
p.popV()
|
|
p.rstack = p.rstack[:len(p.rstack)-1]
|
|
if ok && p.debug {
|
|
p.print(strings.Repeat(" ", p.depth)+"MATCH", string(p.sliceFrom(start)))
|
|
}
|
|
|
|
if p.memoize {
|
|
p.setMemoized(start, rule, resultTuple{val, ok, p.pt})
|
|
}
|
|
return val, ok
|
|
}
|
|
|
|
func (p *parser) parseExpr(expr interface{}) (interface{}, bool) {
|
|
var pt savepoint
|
|
var ok bool
|
|
|
|
if p.memoize {
|
|
res, ok := p.getMemoized(expr)
|
|
if ok {
|
|
p.restore(res.end)
|
|
return res.v, res.b
|
|
}
|
|
pt = p.pt
|
|
}
|
|
|
|
p.exprCnt++
|
|
var val interface{}
|
|
switch expr := expr.(type) {
|
|
case *actionExpr:
|
|
val, ok = p.parseActionExpr(expr)
|
|
case *andCodeExpr:
|
|
val, ok = p.parseAndCodeExpr(expr)
|
|
case *andExpr:
|
|
val, ok = p.parseAndExpr(expr)
|
|
case *anyMatcher:
|
|
val, ok = p.parseAnyMatcher(expr)
|
|
case *charClassMatcher:
|
|
val, ok = p.parseCharClassMatcher(expr)
|
|
case *choiceExpr:
|
|
val, ok = p.parseChoiceExpr(expr)
|
|
case *labeledExpr:
|
|
val, ok = p.parseLabeledExpr(expr)
|
|
case *litMatcher:
|
|
val, ok = p.parseLitMatcher(expr)
|
|
case *notCodeExpr:
|
|
val, ok = p.parseNotCodeExpr(expr)
|
|
case *notExpr:
|
|
val, ok = p.parseNotExpr(expr)
|
|
case *oneOrMoreExpr:
|
|
val, ok = p.parseOneOrMoreExpr(expr)
|
|
case *ruleRefExpr:
|
|
val, ok = p.parseRuleRefExpr(expr)
|
|
case *seqExpr:
|
|
val, ok = p.parseSeqExpr(expr)
|
|
case *zeroOrMoreExpr:
|
|
val, ok = p.parseZeroOrMoreExpr(expr)
|
|
case *zeroOrOneExpr:
|
|
val, ok = p.parseZeroOrOneExpr(expr)
|
|
default:
|
|
panic(fmt.Sprintf("unknown expression type %T", expr))
|
|
}
|
|
if p.memoize {
|
|
p.setMemoized(pt, expr, resultTuple{val, ok, p.pt})
|
|
}
|
|
return val, ok
|
|
}
|
|
|
|
func (p *parser) parseActionExpr(act *actionExpr) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseActionExpr"))
|
|
}
|
|
|
|
start := p.pt
|
|
val, ok := p.parseExpr(act.expr)
|
|
if ok {
|
|
p.cur.pos = start.position
|
|
p.cur.text = p.sliceFrom(start)
|
|
actVal, err := act.run(p)
|
|
if err != nil {
|
|
p.addErrAt(err, start.position)
|
|
}
|
|
val = actVal
|
|
}
|
|
if ok && p.debug {
|
|
p.print(strings.Repeat(" ", p.depth)+"MATCH", string(p.sliceFrom(start)))
|
|
}
|
|
return val, ok
|
|
}
|
|
|
|
func (p *parser) parseAndCodeExpr(and *andCodeExpr) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseAndCodeExpr"))
|
|
}
|
|
|
|
ok, err := and.run(p)
|
|
if err != nil {
|
|
p.addErr(err)
|
|
}
|
|
return nil, ok
|
|
}
|
|
|
|
func (p *parser) parseAndExpr(and *andExpr) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseAndExpr"))
|
|
}
|
|
|
|
pt := p.pt
|
|
p.pushV()
|
|
_, ok := p.parseExpr(and.expr)
|
|
p.popV()
|
|
p.restore(pt)
|
|
return nil, ok
|
|
}
|
|
|
|
func (p *parser) parseAnyMatcher(any *anyMatcher) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseAnyMatcher"))
|
|
}
|
|
|
|
if p.pt.rn != utf8.RuneError {
|
|
start := p.pt
|
|
p.read()
|
|
return p.sliceFrom(start), true
|
|
}
|
|
return nil, false
|
|
}
|
|
|
|
func (p *parser) parseCharClassMatcher(chr *charClassMatcher) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseCharClassMatcher"))
|
|
}
|
|
|
|
cur := p.pt.rn
|
|
// can't match EOF
|
|
if cur == utf8.RuneError {
|
|
return nil, false
|
|
}
|
|
start := p.pt
|
|
if chr.ignoreCase {
|
|
cur = unicode.ToLower(cur)
|
|
}
|
|
|
|
// try to match in the list of available chars
|
|
for _, rn := range chr.chars {
|
|
if rn == cur {
|
|
if chr.inverted {
|
|
return nil, false
|
|
}
|
|
p.read()
|
|
return p.sliceFrom(start), true
|
|
}
|
|
}
|
|
|
|
// try to match in the list of ranges
|
|
for i := 0; i < len(chr.ranges); i += 2 {
|
|
if cur >= chr.ranges[i] && cur <= chr.ranges[i+1] {
|
|
if chr.inverted {
|
|
return nil, false
|
|
}
|
|
p.read()
|
|
return p.sliceFrom(start), true
|
|
}
|
|
}
|
|
|
|
// try to match in the list of Unicode classes
|
|
for _, cl := range chr.classes {
|
|
if unicode.Is(cl, cur) {
|
|
if chr.inverted {
|
|
return nil, false
|
|
}
|
|
p.read()
|
|
return p.sliceFrom(start), true
|
|
}
|
|
}
|
|
|
|
if chr.inverted {
|
|
p.read()
|
|
return p.sliceFrom(start), true
|
|
}
|
|
return nil, false
|
|
}
|
|
|
|
func (p *parser) parseChoiceExpr(ch *choiceExpr) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseChoiceExpr"))
|
|
}
|
|
|
|
for _, alt := range ch.alternatives {
|
|
p.pushV()
|
|
val, ok := p.parseExpr(alt)
|
|
p.popV()
|
|
if ok {
|
|
return val, ok
|
|
}
|
|
}
|
|
return nil, false
|
|
}
|
|
|
|
func (p *parser) parseLabeledExpr(lab *labeledExpr) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseLabeledExpr"))
|
|
}
|
|
|
|
p.pushV()
|
|
val, ok := p.parseExpr(lab.expr)
|
|
p.popV()
|
|
if ok && lab.label != "" {
|
|
m := p.vstack[len(p.vstack)-1]
|
|
m[lab.label] = val
|
|
}
|
|
return val, ok
|
|
}
|
|
|
|
func (p *parser) parseLitMatcher(lit *litMatcher) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseLitMatcher"))
|
|
}
|
|
|
|
start := p.pt
|
|
for _, want := range lit.val {
|
|
cur := p.pt.rn
|
|
if lit.ignoreCase {
|
|
cur = unicode.ToLower(cur)
|
|
}
|
|
if cur != want {
|
|
p.restore(start)
|
|
return nil, false
|
|
}
|
|
p.read()
|
|
}
|
|
return p.sliceFrom(start), true
|
|
}
|
|
|
|
func (p *parser) parseNotCodeExpr(not *notCodeExpr) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseNotCodeExpr"))
|
|
}
|
|
|
|
ok, err := not.run(p)
|
|
if err != nil {
|
|
p.addErr(err)
|
|
}
|
|
return nil, !ok
|
|
}
|
|
|
|
func (p *parser) parseNotExpr(not *notExpr) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseNotExpr"))
|
|
}
|
|
|
|
pt := p.pt
|
|
p.pushV()
|
|
_, ok := p.parseExpr(not.expr)
|
|
p.popV()
|
|
p.restore(pt)
|
|
return nil, !ok
|
|
}
|
|
|
|
func (p *parser) parseOneOrMoreExpr(expr *oneOrMoreExpr) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseOneOrMoreExpr"))
|
|
}
|
|
|
|
var vals []interface{}
|
|
|
|
for {
|
|
p.pushV()
|
|
val, ok := p.parseExpr(expr.expr)
|
|
p.popV()
|
|
if !ok {
|
|
if len(vals) == 0 {
|
|
// did not match once, no match
|
|
return nil, false
|
|
}
|
|
return vals, true
|
|
}
|
|
vals = append(vals, val)
|
|
}
|
|
}
|
|
|
|
func (p *parser) parseRuleRefExpr(ref *ruleRefExpr) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseRuleRefExpr " + ref.name))
|
|
}
|
|
|
|
if ref.name == "" {
|
|
panic(fmt.Sprintf("%s: invalid rule: missing name", ref.pos))
|
|
}
|
|
|
|
rule := p.rules[ref.name]
|
|
if rule == nil {
|
|
p.addErr(fmt.Errorf("undefined rule: %s", ref.name))
|
|
return nil, false
|
|
}
|
|
return p.parseRule(rule)
|
|
}
|
|
|
|
func (p *parser) parseSeqExpr(seq *seqExpr) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseSeqExpr"))
|
|
}
|
|
|
|
var vals []interface{}
|
|
|
|
pt := p.pt
|
|
for _, expr := range seq.exprs {
|
|
val, ok := p.parseExpr(expr)
|
|
if !ok {
|
|
p.restore(pt)
|
|
return nil, false
|
|
}
|
|
vals = append(vals, val)
|
|
}
|
|
return vals, true
|
|
}
|
|
|
|
func (p *parser) parseZeroOrMoreExpr(expr *zeroOrMoreExpr) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseZeroOrMoreExpr"))
|
|
}
|
|
|
|
var vals []interface{}
|
|
|
|
for {
|
|
p.pushV()
|
|
val, ok := p.parseExpr(expr.expr)
|
|
p.popV()
|
|
if !ok {
|
|
return vals, true
|
|
}
|
|
vals = append(vals, val)
|
|
}
|
|
}
|
|
|
|
func (p *parser) parseZeroOrOneExpr(expr *zeroOrOneExpr) (interface{}, bool) {
|
|
if p.debug {
|
|
defer p.out(p.in("parseZeroOrOneExpr"))
|
|
}
|
|
|
|
p.pushV()
|
|
val, _ := p.parseExpr(expr.expr)
|
|
p.popV()
|
|
// whether it matched or not, consider it a match
|
|
return val, true
|
|
}
|
|
|
|
func rangeTable(class string) *unicode.RangeTable {
|
|
if rt, ok := unicode.Categories[class]; ok {
|
|
return rt
|
|
}
|
|
if rt, ok := unicode.Properties[class]; ok {
|
|
return rt
|
|
}
|
|
if rt, ok := unicode.Scripts[class]; ok {
|
|
return rt
|
|
}
|
|
|
|
// cannot happen
|
|
panic(fmt.Sprintf("invalid Unicode class: %s", class))
|
|
}
|