diff options
Diffstat (limited to 'driver/parser.go')
| -rw-r--r-- | driver/parser.go | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/driver/parser.go b/driver/parser.go index cdcaf14..a96f89a 100644 --- a/driver/parser.go +++ b/driver/parser.go @@ -81,6 +81,7 @@ type Parser struct { ast *Node makeAST bool makeCST bool + needSemAct bool } func NewParser(gram *spec.CompiledGrammar, src io.Reader, opts ...ParserOption) (*Parser, error) { @@ -93,7 +94,6 @@ func NewParser(gram *spec.CompiledGrammar, src io.Reader, opts ...ParserOption) gram: gram, lex: lex, stateStack: []int{}, - semStack: []*semanticFrame{}, } for _, opt := range opts { @@ -103,6 +103,8 @@ func NewParser(gram *spec.CompiledGrammar, src io.Reader, opts ...ParserOption) } } + p.needSemAct = p.makeAST || p.makeCST + return p, nil } @@ -130,7 +132,7 @@ func (p *Parser) Parse() error { } // semantic action - { + if p.needSemAct { var ast *Node var cst *Node if p.makeAST { @@ -154,14 +156,17 @@ func (p *Parser) Parse() error { case act > 0: // Reduce accepted := p.reduce(act) if accepted { - top := p.semStack[len(p.semStack)-1] - p.cst = top.cst - p.ast = top.ast + if p.needSemAct { + top := p.semStack[len(p.semStack)-1] + p.cst = top.cst + p.ast = top.ast + } + return nil } // semantic action - { + if p.needSemAct { prodNum := act lhs := p.gram.ParsingTable.LHSSymbols[prodNum] |