/* Starshatter OpenSource Distribution Copyright (c) 1997-2004, Destroyer Studios LLC. All Rights Reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name "Destroyer Studios" nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. 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SUBSYSTEM: Parser FILE: Parser.cpp AUTHOR: John DiCamillo OVERVIEW ======== Implementation of the generic Parser class */ #include "MemDebug.h" #include "Reader.h" #include "Token.h" #include "Parser.h" #include "Term.h" #include #include enum KEYS { KEY_TRUE, KEY_FALSE, KEY_DEF, KEY_MINUS }; void Print(const char* fmt, ...); static int dump_tokens = 0; // +-------------------------------------------------------------------+ Term* error(char* msg, const Token& token) { static char buf[1024]; sprintf_s(buf, " near '%s' in line %d.", (const char*) token.symbol(), token.line()); return error(msg, buf); } // +-------------------------------------------------------------------+ Parser::Parser(Reader* r) { reader = r ? r : new(__FILE__, __LINE__) ConsoleReader; lexer = new(__FILE__, __LINE__) Scanner(reader); Token::addKey("true", KEY_TRUE); Token::addKey("false", KEY_FALSE); Token::addKey(":", KEY_DEF); Token::addKey("-", KEY_MINUS); } Parser::~Parser() { delete lexer; delete reader; //Token::close(); } Term* Parser::ParseTerm() { Term* t = ParseTermBase(); if (t == 0) return t; Term* t2 = ParseTermRest(t); return t2; } Term* Parser::ParseTermRest(Term* base) { Token t = lexer->Get(); switch (t.type()) { default: lexer->PutBack(); return base; case Token::StringLiteral: { // concatenate adjacent string literal tokens: TermText* text = base->isText(); if (text) { TermText* base2 = new(__FILE__, __LINE__) TermText(text->value() + t.symbol()(1, t.symbol().length()-2)); delete base; return ParseTermRest(base2); } else { lexer->PutBack(); } } break; case Token::Keyword: switch (t.key()) { case KEY_DEF: if (base->isText()) return new(__FILE__, __LINE__) TermDef(base->isText(), ParseTerm()); else return error("(Parse) illegal lhs in def", t); default: lexer->PutBack(); return base; } break; } return base; } static int xtol(const char* p) { int n = 0; while (*p) { char digit = *p++; n *= 16; if (digit >= '0' && digit <= '9') n += digit - '0'; else if (digit >= 'a' && digit <= 'f') n += digit - 'a' + 10; else if (digit >= 'A' && digit <= 'F') n += digit - 'A' + 10; } return n; } Term* Parser::ParseTermBase() { Token t = lexer->Get(); int n = 0; double d = 0.0; switch (t.type()) { case Token::IntLiteral: { if (dump_tokens) Print("%s", t.symbol().data()); char nstr[256], *p = nstr; for (int i = 0; i < (int) t.symbol().length(); i++) if (t.symbol()[i] != '_') *p++ = t.symbol()[i]; *p++ = '\0'; // handle hex notation: if (nstr[1] == 'x') n = xtol(nstr+2); else n = atol(nstr); return new(__FILE__, __LINE__) TermNumber(n); } case Token::FloatLiteral: { if (dump_tokens) Print("%s", t.symbol().data()); char nstr[256], *p = nstr; for (int i = 0; i < (int) t.symbol().length(); i++) if (t.symbol()[i] != '_') *p++ = t.symbol()[i]; *p++ = '\0'; d = atof(nstr); return new(__FILE__, __LINE__) TermNumber(d); } case Token::StringLiteral: if (dump_tokens) Print("%s", t.symbol().data()); return new(__FILE__, __LINE__) TermText(t.symbol()(1, t.symbol().length()-2)); case Token::AlphaIdent: if (dump_tokens) Print("%s", t.symbol().data()); return new(__FILE__, __LINE__) TermText(t.symbol()); case Token::Keyword: if (dump_tokens) Print("%s", t.symbol().data()); switch (t.key()) { case KEY_FALSE: return new(__FILE__, __LINE__) TermBool(0); case KEY_TRUE: return new(__FILE__, __LINE__) TermBool(1); case KEY_MINUS: { Token next = lexer->Get(); if (next.type() == Token::IntLiteral) { if (dump_tokens) Print("%s", next.symbol().data()); char nstr[256], *p = nstr; for (int i = 0; i < (int) next.symbol().length(); i++) if (next.symbol()[i] != '_') *p++ = next.symbol()[i]; *p++ = '\0'; n = -1 * atol(nstr); return new(__FILE__, __LINE__) TermNumber(n); } else if (next.type() == Token::FloatLiteral) { if (dump_tokens) Print("%s", next.symbol().data()); char nstr[256], *p = nstr; for (int i = 0; i < (int) next.symbol().length(); i++) if (next.symbol()[i] != '_') *p++ = next.symbol()[i]; *p++ = '\0'; d = -1.0 * atof(nstr); return new(__FILE__, __LINE__) TermNumber(d); } else { lexer->PutBack(); return error("(Parse) illegal token '-': number expected", next); } } break; default: lexer->PutBack(); return 0; } case Token::LParen: return ParseArray(); case Token::LBrace: return ParseStruct(); case Token::CharLiteral: return error("(Parse) illegal token ", t); default: lexer->PutBack(); return 0; } } TermArray* Parser::ParseArray() { TermList* elems = ParseTermList(0); Token end = lexer->Get(); if (end.type() != Token::RParen) return (TermArray*) error("(Parse) ')' missing in array-decl", end); return new(__FILE__, __LINE__) TermArray(elems); } TermStruct* Parser::ParseStruct() { TermList* elems = ParseTermList(1); Token end = lexer->Get(); if (end.type() != Token::RBrace) return (TermStruct*) error("(Parse) '}' missing in struct", end); return new(__FILE__, __LINE__) TermStruct(elems); } TermList* Parser::ParseTermList(int for_struct) { TermList* tlist = new(__FILE__, __LINE__) TermList; Term* term = ParseTerm(); while (term) { if (for_struct && !term->isDef()) { return (TermList*) error("(Parse) non-definition term in struct"); } else if (!for_struct && term->isDef()) { return (TermList*) error("(Parse) illegal definition in array"); } tlist->append(term); Token t = lexer->Get(); /*** OLD WAY: COMMA SEPARATORS REQUIRED *** if (t.type() != Token::Comma) { lexer->PutBack(); term = 0; } else term = ParseTerm(); /*******************************************/ // NEW WAY: COMMA SEPARATORS OPTIONAL: if (t.type() != Token::Comma) { lexer->PutBack(); } term = ParseTerm(); } return tlist; }