71 lines
No EOL
2.6 KiB
C++
71 lines
No EOL
2.6 KiB
C++
#include "compiler/build_tables/first_set.h"
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#include "tree_sitter/compiler.h"
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#include "compiler/prepared_grammar.h"
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#include "compiler/build_tables/rule_can_be_blank.h"
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#include "compiler/rules/metadata.h"
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#include "compiler/rules/visitor.h"
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#include "compiler/rules/seq.h"
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#include "compiler/rules/choice.h"
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#include "compiler/rules/interned_symbol.h"
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namespace tree_sitter {
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using std::set;
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using rules::ISymbol;
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namespace build_tables {
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class FirstSet : public rules::RuleFn<set<ISymbol>> {
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const PreparedGrammar *grammar;
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set<ISymbol> visited_symbols;
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public:
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explicit FirstSet(const PreparedGrammar *grammar) : grammar(grammar) {}
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set<ISymbol> apply_to(const ISymbol *rule) {
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auto insertion_result = visited_symbols.insert(*rule);
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if (insertion_result.second) {
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return (rule->is_token()) ?
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set<ISymbol>({ *rule }) :
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apply(grammar->rule(*rule));
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} else {
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return set<ISymbol>();
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}
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}
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set<ISymbol> apply_to(const rules::Metadata *rule) {
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return apply(rule->rule);
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}
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set<ISymbol> apply_to(const rules::Choice *rule) {
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set<ISymbol> result;
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for (const auto &el : rule->elements) {
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auto &&next_syms = apply(el);
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result.insert(next_syms.begin(), next_syms.end());
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}
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return result;
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}
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set<ISymbol> apply_to(const rules::Seq *rule) {
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auto &&result = apply(rule->left);
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if (rule_can_be_blank(rule->left, *grammar)) {
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auto &&right_symbols = apply(rule->right);
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result.insert(right_symbols.begin(), right_symbols.end());
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}
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return result;
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}
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};
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set<ISymbol> first_set(const rules::rule_ptr &rule, const PreparedGrammar &grammar) {
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return FirstSet(&grammar).apply(rule);
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}
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set<ISymbol> first_set(const ParseItemSet &item_set, const PreparedGrammar &grammar) {
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set<ISymbol> result;
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for (auto &item : item_set) {
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auto &&rule_set = first_set(item.rule, grammar);
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result.insert(rule_set.begin(), rule_set.end());
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if (rule_can_be_blank(item.rule, grammar))
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result.insert(item.lookahead_sym);
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}
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return result;
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}
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}
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} |