traxys/tree-sitter
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Refactor rule visitors

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This commit is contained in:
Max Brunsfeld 2014-02-23 18:04:51 -08:00
parent 713b3899c5
commit 2c30dce08e
6 changed files with 100 additions and 138 deletions
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25
src/compiler/build_tables/first_set.cpp
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@ -11,11 +11,10 @@ namespace tree_sitter {
using namespace rules;
namespace build_tables {
class FirstSetVisitor : Visitor {
set<Symbol> value;
class FirstSet : public RuleFn<set<Symbol>> {
const PreparedGrammar grammar;
FirstSetVisitor(const PreparedGrammar &grammar) : grammar(grammar) {}
public:
FirstSet(const PreparedGrammar &grammar) : grammar(grammar) {}
set<Symbol> set_union(const set<Symbol> &left, const set<Symbol> &right) {
set<Symbol> result = left;
@ -25,33 +24,27 @@ namespace tree_sitter {
void visit(const Symbol *rule) {
if (grammar.has_definition(*rule)) {
value = apply(grammar.rule(*rule), grammar);
value = apply(grammar.rule(*rule));
} else {
value = set<Symbol>({ *rule });
}
}
void visit(const Choice *rule) {
value = set_union(apply(rule->left, grammar), apply(rule->right, grammar));
value = set_union(apply(rule->left), apply(rule->right));
}
void visit(const Seq *rule) {
value = apply(rule->left, grammar);
auto result = apply(rule->left);
if (rule_can_be_blank(rule->left, grammar)) {
value = set_union(value, apply(rule->right, grammar));
result = set_union(result, apply(rule->right));
}
}
public:
static set<Symbol> apply(const rule_ptr rule, const PreparedGrammar &grammar) {
FirstSetVisitor visitor(grammar);
rule->accept(visitor);
return visitor.value;
value = result;
}
};
set<Symbol> first_set(const rule_ptr &rule, const PreparedGrammar &grammar) {
return FirstSetVisitor::apply(rule, grammar);
return FirstSet(grammar).apply(rule);
}
}
}