SAWYER_EXPORT std::string
Grammar::evalFunction(TokenStream &tokens, ErrorLocation &eloc) const {
ASSERT_require(tokens.isa(TOK_FUNCTION));
std::string funcName = tokens.lexeme();
ASSERT_require(funcName.size() >= 2 && '@' == funcName[0]);
funcName = funcName.substr(1);
tokens.consume();
// Get the function declaration
const Function::Ptr func = functions_.getOrDefault(funcName);
if (!func)
throw SyntaxError("function \"" + funcName + "\" is not declared");
// Parse the actual arguments
std::vector<std::string> actuals;
while (tokens.isa(TOK_LEFT)) {
tokens.consume();
if (func->isMacro()) {
actuals.push_back(readArgument(tokens, eloc, CONSUME));
} else {
actuals.push_back(evalArgument(tokens, eloc, CONSUME));
}
}
func->validateArgs(actuals, tokens);
ErrorLocation::Trap t(eloc, tokens, "in function \"" + funcName + "\"");
std::string retval = func->eval(*this, actuals);
t.passed();
return retval;
}
SAWYER_EXPORT std::string
Grammar::evalArgument(TokenStream &tokens, ErrorLocation &eloc, bool requireRight) const {
std::string retval, data;
size_t depth = 0;
while (!tokens.atEof()) {
if (tokens.isa(TOK_LEFT)) {
++depth;
retval += tokens.lexeme();
tokens.consume();
} else if (tokens.isa(TOK_RIGHT)) {
if (0 == depth)
break;
--depth;
retval += tokens.lexeme();
tokens.consume();
} else if (tokens.isa(TOK_FUNCTION)) {
retval += evalFunction(tokens, eloc);
} else {
retval += tokens.lexeme();
tokens.consume();
}
}
if (requireRight) {
if (!tokens.isa(TOK_RIGHT))
throw SyntaxError("end-of-argument expected");
tokens.consume();
}
if (depth > 0)
throw SyntaxError("expected end-of-argument marker");
return retval;
}
SAWYER_EXPORT std::string
Grammar::eval(TokenStream &tokens, ErrorLocation &eloc) const {
std::string retval;
while (!tokens.atEof()) {
retval += evalArgument(tokens, eloc, LEAVE);
if (tokens.isa(TOK_RIGHT))
throw SyntaxError("unexpected end-of-argument");
}
return retval;
}
SAWYER_EXPORT std::string
Grammar::readArgument(TokenStream &tokens, ErrorLocation &eloc, bool requireRight) const {
std::string retval;
size_t depth = 0;
for (/*void*/; !tokens.atEof(); tokens.consume()) {
if (tokens.isa(TOK_LEFT)) {
++depth;
} else if (tokens.isa(TOK_RIGHT)) {
if (0 == depth)
break;
--depth;
}
retval += tokens.lexeme();
}
if (requireRight) {
if (!tokens.isa(TOK_RIGHT))
throw SyntaxError("end-of-argument expected");
tokens.consume();
}
if (depth > 0)
throw SyntaxError("expected end-of-argument marker");
return retval;
}