diff options
| -rw-r--r-- | cmd/vartan/describe.go | 34 | ||||
| -rw-r--r-- | grammar/grammar.go | 15 | ||||
| -rw-r--r-- | grammar/parsing_table.go | 30 | ||||
| -rw-r--r-- | spec/description.go | 20 |
4 files changed, 85 insertions, 14 deletions
diff --git a/cmd/vartan/describe.go b/cmd/vartan/describe.go index d9c3b01..c2cde93 100644 --- a/cmd/vartan/describe.go +++ b/cmd/vartan/describe.go @@ -153,12 +153,40 @@ func writeDescription(w io.Writer, desc *spec.Description) error { return "No conflict was detected." }, "printTerminal": func(term spec.Terminal) string { + var prec string + if term.Precedence != 0 { + prec = fmt.Sprintf("%2v", term.Precedence) + } else { + prec = " -" + } + + var assoc string + if term.Associativity != "" { + assoc = term.Associativity + } else { + assoc = "-" + } + if term.Alias != "" { - return fmt.Sprintf("%4v %v (%v)", term.Number, term.Name, term.Alias) + return fmt.Sprintf("%4v %v %v %v (%v)", term.Number, prec, assoc, term.Name, term.Alias) } - return fmt.Sprintf("%4v %v", term.Number, term.Name) + return fmt.Sprintf("%4v %v %v %v", term.Number, prec, assoc, term.Name) }, "printProduction": func(prod spec.Production) string { + var prec string + if prod.Precedence != 0 { + prec = fmt.Sprintf("%2v", prod.Precedence) + } else { + prec = " -" + } + + var assoc string + if prod.Associativity != "" { + assoc = prod.Associativity + } else { + assoc = "-" + } + var b strings.Builder fmt.Fprintf(&b, "%v →", nonTermName(prod.LHS)) if len(prod.RHS) > 0 { @@ -173,7 +201,7 @@ func writeDescription(w io.Writer, desc *spec.Description) error { fmt.Fprintf(&b, " ε") } - return fmt.Sprintf("%4v %v", prod.Number, b.String()) + return fmt.Sprintf("%4v %v %v %v", prod.Number, prec, assoc, b.String()) }, "printItem": func(item spec.Item) string { prod := desc.Productions[item.Production] diff --git a/grammar/grammar.go b/grammar/grammar.go index edfb6af..b87d368 100644 --- a/grammar/grammar.go +++ b/grammar/grammar.go @@ -33,8 +33,9 @@ const ( // precAndAssoc represents precedence and associativities of terminal symbols and productions. // We use the priority of the production to resolve shift/reduce conflicts. type precAndAssoc struct { - // termPrec represents the precedence of the terminal symbols. - termPrec map[symbolNum]int + // termPrec and termAssoc represent the precedence of the terminal symbols. + termPrec map[symbolNum]int + termAssoc map[symbolNum]assocType // prodPrec and prodAssoc represent the precedence and the associativities of the production. // These values are inherited from the right-most symbols in the RHS of the productions. @@ -51,6 +52,15 @@ func (pa *precAndAssoc) terminalPrecedence(sym symbolNum) int { return prec } +func (pa *precAndAssoc) terminalAssociativity(sym symbolNum) assocType { + assoc, ok := pa.termAssoc[sym] + if !ok { + return assocTypeNil + } + + return assoc +} + func (pa *precAndAssoc) productionPredence(prod productionNum) int { prec, ok := pa.prodPrec[prod] if !ok { @@ -896,6 +906,7 @@ func (b *GrammarBuilder) genPrecAndAssoc(symTab *symbolTable, prods *productionS return &precAndAssoc{ termPrec: termPrec, + termAssoc: termAssoc, prodPrec: prodPrec, prodAssoc: prodAssoc, }, nil diff --git a/grammar/parsing_table.go b/grammar/parsing_table.go index fe5a619..a82ef60 100644 --- a/grammar/parsing_table.go +++ b/grammar/parsing_table.go @@ -347,6 +347,19 @@ func (b *lrTableBuilder) genDescription(tab *ParsingTable, gram *Grammar) (*spec term.Pattern = pat } + prec := b.precAndAssoc.terminalPrecedence(sym.num()) + if prec != precNil { + term.Precedence = prec + } + + assoc := b.precAndAssoc.terminalAssociativity(sym.num()) + switch assoc { + case assocTypeLeft: + term.Associativity = "l" + case assocTypeRight: + term.Associativity = "r" + } + terms[sym.num()] = term } } @@ -382,11 +395,26 @@ func (b *lrTableBuilder) genDescription(tab *ParsingTable, gram *Grammar) (*spec } } - prods[p.num.Int()] = &spec.Production{ + prod := &spec.Production{ Number: p.num.Int(), LHS: p.lhs.num().Int(), RHS: rhs, } + + prec := b.precAndAssoc.productionPredence(p.num) + if prec != precNil { + prod.Precedence = prec + } + + assoc := b.precAndAssoc.productionAssociativity(p.num) + switch assoc { + case assocTypeLeft: + prod.Associativity = "l" + case assocTypeRight: + prod.Associativity = "r" + } + + prods[p.num.Int()] = prod } } diff --git a/spec/description.go b/spec/description.go index d2b6d3b..08b037e 100644 --- a/spec/description.go +++ b/spec/description.go @@ -1,11 +1,13 @@ package spec type Terminal struct { - Number int `json:"number"` - Name string `json:"name"` - Anonymous bool `json:"anonymous"` - Alias string `json:"alias"` - Pattern string `json:"pattern"` + Number int `json:"number"` + Name string `json:"name"` + Anonymous bool `json:"anonymous"` + Alias string `json:"alias"` + Pattern string `json:"pattern"` + Precedence int `json:"prec"` + Associativity string `json:"assoc"` } type NonTerminal struct { @@ -14,9 +16,11 @@ type NonTerminal struct { } type Production struct { - Number int `json:"number"` - LHS int `json:"lhs"` - RHS []int `json:"rhs"` + Number int `json:"number"` + LHS int `json:"lhs"` + RHS []int `json:"rhs"` + Precedence int `json:"prec"` + Associativity string `json:"assoc"` } type Item struct { |