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#include <boost/algorithm/string.hpp>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include <deque>
#include <map>
#include <string>
#include <utility>
#include <vector>
using namespace std::string_literals;
using BNF = std::map<std::string, std::vector<std::vector<std::string>>>;
using Terminals = std::set<std::string>;
using ProgramNode = std::deque<std::string>;
using PathElement = std::pair<std::string, size_t>; // Name, Index
std::vector<std::string> split(std::string s)
{
std::vector<std::string> result;
boost::algorithm::split(result, s, boost::algorithm::is_any_of(s), boost::algorithm::token_compress_on);
while (result.size() > 0 && result.back() == ""s)
result.pop_back();
return result;
}
std::vector<PathElement> GetPath(std::string Token, BNF ReverseBNF, std::string Top, Terminals terminals = {}, std::vector<PathElement> PreviousPath = {})
{
throw std::runtime_error("Compile error");
return {}; // TODO
}
BNF Reverse(BNF bnf){
return {}; // TODO
}
using index_t = size_t;
struct TreeNode {
index_t parent;
std::vector<index_t> childs;
std::string name;
};
struct Tree {
std::map<index_t, TreeNode> nodes; // index 0 = non existing; index starting at 1
index_t node_num{};
index_t root{};
index_t last{};
bool Valid() const {
// Start symbol?
// All terminal symbols?
return true; // TODO
}
bool Add(char c) {
// TODO
//node_num ++;
//nodes.emplace(node_num, {});
return false;
}
};
void CheckCandidates(std::deque<Tree>& candidates, std::string& token, std::vector<std::string>& result)
{
bool valid{false};
for (const auto& ct : candidates) {
if (ct.Valid()) {
if (valid)
throw std::runtime_error("Found ambiguous token "s + token);
result.push_back(token);
token.clear();
valid = true;
}
}
if (!valid)
throw std::runtime_error("Invalid token: "s + token);
candidates.clear();
}
std::vector<std::string> Lex(std::string s, std::string Top, BNF bnf)
{
std::vector<std::string> result;
std::string token;
BNF ReverseBNF{ Reverse(bnf)};
std::string Whitespace{"\t \n\r"};
std::deque<Tree> candidates;
for (size_t pos{0}; pos < s.size(); pos++) {
char c{s[pos]};
if (Whitespace.find(c) != std::string::npos) { // found whitespace character
if (candidates.empty()) { // skip
if (!token.empty())
throw std::runtime_error("Expected empty token, got "s + token);
} else { // check candidates
CheckCandidates(candidates, token, result);
}
} else { // no whitespace: try to add to tree
std::deque<index_t> EraseList;
int i = 0;
for (auto ct = candidates.begin(); ct != candidates.end(); ct++, i++) {
if (!ct->Add(c)) {
EraseList.push_front(i); // no candidate anymore
}
}
// new candidate: starting with c
auto element {ReverseBNF.find(std::string(1, c))};
if (element != ReverseBNF.end()) {
candidates.emplace_back();
candidates.back().Add(c);
}
if (candidates.size() - EraseList.size() > 0) { // Added to some candidates: Continue growing token
token.push_back(c);
for (const auto& i : EraseList)
candidates.erase(candidates.begin() + i);
} else { // no candidates left: new tree
CheckCandidates(candidates, token, result);
}
}
}
// Final evaluation
if (candidates.empty()) { // skip
if (!token.empty())
throw std::runtime_error("Expected empty token at end of input, got "s + token);
} else { // check candidates
CheckCandidates(candidates, token, result);
}
return result;
}
ProgramNode Compile(std::vector<std::string> Tokens, std::string Top, BNF bnf, Terminals terminals)
{
BNF ReverseBNF{ Reverse(bnf)};
if (Tokens.size()){
std::string Token = Tokens[0];
auto Path = GetPath(Token, ReverseBNF, Top, terminals);
if (Path.size()) {
size_t Index{1};
while (Index < Tokens.size()) {
Path = GetPath(Token, ReverseBNF, Top, terminals, Path);
Index++;
}
} else
throw std::runtime_error("Invalid token: "s + Token);
} else
throw std::runtime_error("No tokens!");
return {};
}
class Test: public ::testing::Test {
protected:
Test(){}
~Test() override {}
};
TEST_F(Test, BNF) {
std::string LexTop{"preprocessing-token"};
BNF LexBNF{
{"preprocessing-token", {{"identifier"},
{"preprocessing-op-or-punc"},
{"pp-number"}}},
{"identifier", {{"identifier-nondigit"},
{"identifier", "identifier-nondigit"},
{"identifier", "digit"}}},
{"digit", {{"0", "1", "2", "3", "4", "5", "6", "7", "8", "9" }}},
{"identifier-nondigit", {{"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z",
"A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "_"}}},
{"preprocessing-op-or-punc", {{";"},
{"="}}},
{"pp-number", {{"digit"},
{"pp-number", "digit"}}}
};
std::string Top{"program"};
BNF bnf{
{"program", {{"statement-list"}}},
{"statement-list", {{"statement", "statement-list"},
{}, }},
{"statement", {{"assigmnent", ";"}}},
{"assignment", {{"identifier", "=", "identifier"}}}
};
std::set<std::string> Terminals{"identifier", "=", ";"};
std::string Code{"a = b ; c = d ; e = f ;"};
auto tokens = Lex(Code, LexTop, LexBNF);
auto Program = Compile(tokens, Top, bnf, Terminals);
}
int main(int argc, char* argv[]) {
::testing::InitGoogleMock(&argc, argv);
return RUN_ALL_TESTS();
}
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