diff options
Diffstat (limited to 'grammar/grammar.go')
| -rw-r--r-- | grammar/grammar.go | 61 |
1 files changed, 16 insertions, 45 deletions
diff --git a/grammar/grammar.go b/grammar/grammar.go index 80846d9..e2f9ba0 100644 --- a/grammar/grammar.go +++ b/grammar/grammar.go @@ -84,7 +84,6 @@ type Grammar struct { name string lexSpec *mlspec.LexSpec skipLexKinds []mlspec.LexKindName - kindAliases map[symbol]string sym2AnonPat map[symbol]string productionSet *productionSet augmentedStartSymbol symbol @@ -212,7 +211,6 @@ func (b *GrammarBuilder) Build() (*Grammar, error) { name: specName, lexSpec: symTabAndLexSpec.lexSpec, skipLexKinds: symTabAndLexSpec.skip, - kindAliases: symTabAndLexSpec.aliases, sym2AnonPat: symTabAndLexSpec.sym2AnonPat, productionSet: prodsAndActs.prods, augmentedStartSymbol: prodsAndActs.augStartSym, @@ -392,7 +390,6 @@ type symbolTableAndLexSpec struct { errSym symbol skip []mlspec.LexKindName skipSyms []string - aliases map[symbol]string } func (b *GrammarBuilder) genSymbolTableAndLexSpec(root *spec.RootNode) (*symbolTableAndLexSpec, error) { @@ -413,7 +410,6 @@ func (b *GrammarBuilder) genSymbolTableAndLexSpec(root *spec.RootNode) (*symbolT anonPat2Sym := map[string]symbol{} sym2AnonPat := map[symbol]string{} - aliases := map[symbol]string{} { knownPats := map[string]struct{}{} anonPats := []string{} @@ -456,10 +452,6 @@ func (b *GrammarBuilder) genSymbolTableAndLexSpec(root *spec.RootNode) (*symbolT anonPat2Sym[p] = sym sym2AnonPat[sym] = p - if _, ok := literalPats[p]; ok { - aliases[sym] = p - } - entries = append(entries, &mlspec.LexEntry{ Kind: mlspec.LexKindName(kind), Pattern: mlspec.LexPattern(p), @@ -489,12 +481,12 @@ func (b *GrammarBuilder) genSymbolTableAndLexSpec(root *spec.RootNode) (*symbolT continue } - lhsSym, err := symTab.registerTerminalSymbol(prod.LHS) + _, err := symTab.registerTerminalSymbol(prod.LHS) if err != nil { return nil, err } - entry, skip, alias, specErr, err := genLexEntry(prod) + entry, skip, specErr, err := genLexEntry(prod) if err != nil { return nil, err } @@ -506,9 +498,6 @@ func (b *GrammarBuilder) genSymbolTableAndLexSpec(root *spec.RootNode) (*symbolT skipKinds = append(skipKinds, mlspec.LexKindName(prod.LHS)) skipSyms = append(skipSyms, prod.LHS) } - if alias != "" { - aliases[lhsSym] = alias - } entries = append(entries, entry) } @@ -542,19 +531,16 @@ func (b *GrammarBuilder) genSymbolTableAndLexSpec(root *spec.RootNode) (*symbolT errSym: errSym, skip: skipKinds, skipSyms: skipSyms, - aliases: aliases, }, nil } -func genLexEntry(prod *spec.ProductionNode) (*mlspec.LexEntry, bool, string, *verr.SpecError, error) { +func genLexEntry(prod *spec.ProductionNode) (*mlspec.LexEntry, bool, *verr.SpecError, error) { alt := prod.RHS[0] elem := alt.Elements[0] var pattern string - var alias string if elem.Literally { pattern = mlspec.EscapePattern(elem.Pattern) - alias = elem.Pattern } else { pattern = elem.Pattern } @@ -566,7 +552,7 @@ func genLexEntry(prod *spec.ProductionNode) (*mlspec.LexEntry, bool, string, *ve dirConsumed := map[string]struct{}{} for _, dir := range prod.Directives { if _, consumed := dirConsumed[dir.Name]; consumed { - return nil, false, "", &verr.SpecError{ + return nil, false, &verr.SpecError{ Cause: semErrDuplicateDir, Detail: dir.Name, Row: dir.Pos.Row, @@ -578,7 +564,7 @@ func genLexEntry(prod *spec.ProductionNode) (*mlspec.LexEntry, bool, string, *ve switch dir.Name { case "mode": if len(dir.Parameters) == 0 { - return nil, false, "", &verr.SpecError{ + return nil, false, &verr.SpecError{ Cause: semErrDirInvalidParam, Detail: "'mode' directive needs an ID parameter", Row: dir.Pos.Row, @@ -587,7 +573,7 @@ func genLexEntry(prod *spec.ProductionNode) (*mlspec.LexEntry, bool, string, *ve } for _, param := range dir.Parameters { if param.ID == "" { - return nil, false, "", &verr.SpecError{ + return nil, false, &verr.SpecError{ Cause: semErrDirInvalidParam, Detail: "'mode' directive needs an ID parameter", Row: param.Pos.Row, @@ -598,7 +584,7 @@ func genLexEntry(prod *spec.ProductionNode) (*mlspec.LexEntry, bool, string, *ve } case "skip": if len(dir.Parameters) > 0 { - return nil, false, "", &verr.SpecError{ + return nil, false, &verr.SpecError{ Cause: semErrDirInvalidParam, Detail: "'skip' directive needs no parameter", Row: dir.Pos.Row, @@ -608,7 +594,7 @@ func genLexEntry(prod *spec.ProductionNode) (*mlspec.LexEntry, bool, string, *ve skip = true case "push": if len(dir.Parameters) != 1 || dir.Parameters[0].ID == "" { - return nil, false, "", &verr.SpecError{ + return nil, false, &verr.SpecError{ Cause: semErrDirInvalidParam, Detail: "'push' directive needs an ID parameter", Row: dir.Pos.Row, @@ -618,7 +604,7 @@ func genLexEntry(prod *spec.ProductionNode) (*mlspec.LexEntry, bool, string, *ve push = mlspec.LexModeName(dir.Parameters[0].ID) case "pop": if len(dir.Parameters) > 0 { - return nil, false, "", &verr.SpecError{ + return nil, false, &verr.SpecError{ Cause: semErrDirInvalidParam, Detail: "'pop' directive needs no parameter", Row: dir.Pos.Row, @@ -626,18 +612,8 @@ func genLexEntry(prod *spec.ProductionNode) (*mlspec.LexEntry, bool, string, *ve }, nil } pop = true - case "alias": - if len(dir.Parameters) != 1 || dir.Parameters[0].String == "" { - return nil, false, "", &verr.SpecError{ - Cause: semErrDirInvalidParam, - Detail: "'alias' directive needs a string parameter", - Row: dir.Pos.Row, - Col: dir.Pos.Col, - }, nil - } - alias = dir.Parameters[0].String default: - return nil, false, "", &verr.SpecError{ + return nil, false, &verr.SpecError{ Cause: semErrDirInvalidName, Detail: dir.Name, Row: dir.Pos.Row, @@ -647,7 +623,7 @@ func genLexEntry(prod *spec.ProductionNode) (*mlspec.LexEntry, bool, string, *ve } if len(alt.Directives) > 0 { - return nil, false, "", &verr.SpecError{ + return nil, false, &verr.SpecError{ Cause: semErrInvalidAltDir, Detail: "a lexical production cannot have alternative directives", Row: alt.Directives[0].Pos.Row, @@ -661,7 +637,7 @@ func genLexEntry(prod *spec.ProductionNode) (*mlspec.LexEntry, bool, string, *ve Pattern: mlspec.LexPattern(pattern), Push: push, Pop: pop, - }, skip, alias, nil, nil + }, skip, nil, nil } type productionsAndActions struct { @@ -1345,14 +1321,10 @@ func Compile(gram *Grammar, opts ...CompileOption) (*spec.CompiledGrammar, *spec } terms := make([]string, len(termTexts)) for i, t := range termTexts { - if !strings.HasPrefix(t, "x_") { - terms[i] = t - } - } - - kindAliases := make([]string, gram.symbolTable.termNum.Int()) - for _, sym := range gram.symbolTable.terminalSymbols() { - kindAliases[sym.num().Int()] = gram.kindAliases[sym] + // NOTE: For anonymous symbol, `t` is a name with `x_` as a prefix. However, + // this name is not intentionally set by a user, so a message containing this + // name will result in an unfriendly message. + terms[i] = t } nonTerms, err := gram.symbolTable.nonTerminalTexts() @@ -1444,7 +1416,6 @@ func Compile(gram *Grammar, opts ...CompileOption) (*spec.CompiledGrammar, *spec Spec: lexSpec, KindToTerminal: kind2Term, Skip: skip, - KindAliases: kindAliases, }, }, ParsingTable: &spec.ParsingTable{ |