/// <summary>
/// It detects global scope elements and calls special handler
/// </summary>
/// <param name="module"></param>
/// <param name="pos"></param>
/// <returns>Position of a next lexeme</returns>
private int FindElement(LexemeModule module, int pos)
{
if (module.Lexemes[pos].Code == Lexeme.CodeType.Reserved)
{
switch (module.Lexemes[pos].Source)
{
case "using":
break;
case "function":
return(ParseFunctionDeclaration(module, pos));
case "class":
break;
case "constexpr":
break;
default:
Compilation.WriteError("Unknown word: '" + module.Lexemes[pos] + "'.",
module.Lexemes[pos].Line);
break;
}
}
return(pos);
}
/// <summary>
/// Parse variable declaration at function declaration
/// </summary>
/// <param name="module">Module</param>
/// <param name="pos">Position of current parsed lexeme</param>
/// <param name="assertOnUnknownType">Generate error if type isn't defined</param>
/// <param name="typeName">Variable type</param>
/// <param name="varName">Variable name</param>
/// <param name="initElements">Lexemes that inialize this variable. The length can be zero if there no default value</param>
/// <returns>Position of a next lexeme</returns>
private int ParseFuncVarDeclaration(LexemeModule module, int pos, bool assertOnUnknownType,
out string typeName, out string varName, out Lexemes initElements)
{
Compilation.Assert(m_symbols.IsTypeExist(module.Lexemes[pos].Source) ||
(!assertOnUnknownType && module.Lexemes[pos].Code == Lexeme.CodeType.Name),
"Type '" + module.Lexemes[pos] + "' does not exist", module.Lexemes[pos].Line);
typeName = module.Lexemes[pos].Source;
++pos;
Compilation.Assert(module.Lexemes[pos].Code == Lexeme.CodeType.Name,
"Name '" + module.Lexemes[pos].Source + "' is not correct", module.Lexemes[pos].Line);
varName = module.Lexemes[pos].Source;
++pos;
initElements = new Lexemes();
if (module.Lexemes[pos].Source == "=")
{
++pos;
int argScopeLevel = 0;
while (true)
{
if (module.Lexemes[pos].Source == "(")
{
++argScopeLevel;
}
else if (module.Lexemes[pos].Source == ")")
{
--argScopeLevel;
if (argScopeLevel < 0)
{
break;
}
}
else if (module.Lexemes[pos].Source == ",")
{
if (argScopeLevel == 0)
{
break;
}
}
initElements.Add(module.Lexemes[pos]);
++pos;
}
}
return(pos);
}
/// <summary>
/// Extract function body in a list of lexemes
/// </summary>
/// <param name="module">Module</param>
/// <param name="pos">Position of current parsed lexeme</param>
/// <param name="blockLexemes">Function body lexemes</param>
/// <returns>Position of a next lexeme</returns>
private int ExtractBlock(LexemeModule module, int pos, out Lexemes blockLexemes)
{
Compilation.Assert(module.Lexemes[pos].Source == "{", "Did you forget '{' ?", module.Lexemes[pos].Line);
int level = 0;
++pos;
++level;
blockLexemes = new Lexemes();
while (true)
{
if (pos >= module.Lexemes.Count)
{
Compilation.WriteError("Did you forget '}' ?", module.Lexemes[pos - 1].Line);
}
if (module.Lexemes[pos].Source == "{")
{
++level;
}
else if (module.Lexemes[pos].Source == "}")
{
--level;
if (level == 0)
{
++pos;
break;
}
}
blockLexemes.Add(module.Lexemes[pos]);
++pos;
}
return(pos);
}
/// <summary>
/// Parse function declaration and save it. (Function body is parsed at second pass)
/// </summary>
/// <param name="module"></param>
/// <param name="pos"></param>
/// <returns>Position of a next lexeme</returns>
private int ParseFunctionDeclaration(LexemeModule module, int pos)
{
++pos; //skip "function"
Compilation.Assert(module.Lexemes[pos].Code == Lexeme.CodeType.Name,
"Invalid function name: '" + module.Lexemes[pos].Source + "'.", module.Lexemes[pos].Line);
var functionName = module.Lexemes[pos].Source;
++pos;
Compilation.Assert(module.Lexemes[pos].Source == "(", "Did you forget the '(' ?", module.Lexemes[pos].Line);
++pos;
var args = new List <LanguageFunction.FunctionArg>();
var argsInitLexemes = new List <Lexemes>();
if (module.Lexemes[pos].Source != ")")
{
while (true)
{
string typeName;
string varName;
Lexemes initElements;
pos = ParseFuncVarDeclaration(module, pos, false, out typeName, out varName, out initElements);
args.Add(new LanguageFunction.FunctionArg
{
TypeInfo = m_symbols.GetTypeByName(typeName),
ArgName = varName,
DefaultVal = null /*Will be set in the 2nd pass*/
});
argsInitLexemes.Add(initElements);
if (module.Lexemes[pos].Source == ")")
{
break;
}
else if (module.Lexemes[pos].Source == ",")
{
++pos;
}
else
{
Compilation.WriteError("Expected ',' or ')', but found '" + module.Lexemes[pos].Source + "'.",
module.Lexemes[pos].Line);
}
}
}
++pos; //skip ")"
Compilation.Assert(module.Lexemes[pos].Source == "->", "Did you forget the '->' ?",
module.Lexemes[pos].Line);
++pos;
bool hasOneReturnVar = true;
if (module.Lexemes[pos].Source == "(")
{
hasOneReturnVar = false;
++pos;
}
List <string> returnVars = new List <string>();
do
{
Compilation.Assert(module.Lexemes[pos].Code == Lexeme.CodeType.Reserved ||
module.Lexemes[pos].Code == Lexeme.CodeType.Name,
"'" + module.Lexemes[pos].Source + "' can't be a type", module.Lexemes[pos].Line);
returnVars.Add(module.Lexemes[pos].Source);
++pos;
if (hasOneReturnVar)
{
break;
}
if (module.Lexemes[pos].Source == ")")
{
++pos;
break;
}
if (module.Lexemes[pos].Source != ",")
{
Compilation.WriteError("Expected ',', but found '" + module.Lexemes[pos].Source + "'.",
module.Lexemes[pos].Line);
}
++pos;
} while (true);
var funcInfo = new LanguageFunction
{
Name = functionName,
Arguments = args,
ReturnTypes = returnVars.Select(typeName =>
m_symbols.GetTypeByName(typeName))
.ToList()
};
bool ok = m_symbols.AddUserFunction(funcInfo);
if (!ok)
{
Compilation.WriteError("Function " + funcInfo.Name + "' with arguments ["
+ funcInfo.Arguments.Select(arg => arg.TypeInfo.Name)
.Aggregate((arg1, arg2) => arg1 + ", " + arg2)
+ "] already exists", module.Lexemes[pos].Line);
}
Lexemes funcLexemes;
pos = ExtractBlock(module, pos, out funcLexemes);
m_foundedFunctions.Add(new Parser1To2Pass.FunctionInfo
{
Info = funcInfo,
FuncLexemes = funcLexemes,
ArgInitLexemes = argsInitLexemes,
ModuleName = module.FileName
});
return(pos);
}