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#pragma once
#include "bnf.h"
#include "minicc.h"
#include <cstdint>
#include <deque>
#include <tuple>
#include <unordered_set>
#include <utility>
class GrammerTest;
namespace Gram {
struct NodePosition {
index_t node_id{}; // 0-based
index_t child_pos{}; // 0-based
};
// TreeNodes are only intermediate. Terminal symbols don't get TreeNodes
// token_id: index into token list
// node_id: index into tree node list
struct TreeNode {
NodePosition pos; // position of this node in tree (i.e. parent node_id + child_pos in parent)
index_t node_id{}; // this node's id
std::string type;
index_t variant; // bnf[type][variant]
std::vector<int32_t> child_ids; // < 0: terminal: token_id; > 0: non-terminal: node_id; = 0: unset
};
class Compiler
{
private:
// The result
std::vector<TreeNode> nodes;
// Input
std::vector<Token> tokens;
BNF m_bnf; // not const for access via operator[]
const std::string m_top;
std::unordered_map<std::string, std::unordered_set<std::pair<std::string, index_t>, PairHash>> reversedPosFirst; // possible parent types of first childs of a given type
std::deque<index_t> symbol_variants;
decltype(symbol_variants)::iterator symbol_variants_it;
// Tree specific
void clear();
// Node specific
std::string GetTypeOfNode(index_t node_id) const;
index_t AddNode(const std::string& type, index_t variant, NodePosition pos = {});
// Adds actually used Non-Terminal Symbol Removes it on scope exit (RAII)
class AddNodeGuard {
Compiler& m_compiler;
public:
AddNodeGuard(Compiler& compiler, index_t variant);
~AddNodeGuard();
};
void IncNodePosition(NodePosition& pos);
// top-down algorithm
std::unordered_map<std::string, size_t> m_min; // cache for MinimumSymbolsNeeded
size_t minimumSymbolsNeeded(const std::string& symbol);
size_t minimumSymbolsNeeded(const std::vector<std::string>& symbol_list);
bool match(std::string symbol, size_t begin, size_t end);
bool match(std::vector<std::string> symbol_list, size_t begin, size_t end);
// start / end cache
struct TupleHash {
size_t operator()(const std::tuple<std::string,size_t,std::string>& t) const noexcept
{
size_t h0 {std::hash<std::string>{}(std::get<0>(t))};
size_t h1 {std::hash<size_t >{}(std::get<1>(t))};
size_t h2 {std::hash<std::string>{}(std::get<2>(t))};
return h0 ^ (h1 << 1) ^ (h2 << 2);
}
};
// map combination of non-terminal+terminal symbol combination to list of
// possible BNF positions for the specified non-terminal symbol
std::unordered_map<std::pair<std::string, std::string>, std::vector<size_t>, PairHashSS> m_match_lut;
std::unordered_map<std::string, size_t> m_empty_lut; // list of non-terminal symbols that can lead to empty token list (maps to variant)
void fillStartCache();
void constructTree();
public:
Compiler(BNF& bnf, const std::string& top);
std::vector<TreeNode> compile(std::vector<Token> p_tokens);
void DumpTree();
friend class ::GrammerTest;
};
bool ChildIdIsEmpty(int32_t child_id);
bool ChildIdIsToken(int32_t child_id);
bool ChildIdIsNode(int32_t child_id);
index_t TokenIdFromChildId(int32_t child_id);
int32_t ChildIdFromTokenId(index_t token_id);
} // namespace Gram
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