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Diffstat (limited to 'grammar')
-rw-r--r--grammar/grammar.go15
-rw-r--r--grammar/parsing_table.go30
2 files changed, 42 insertions, 3 deletions
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
}
}