public static FunctionDeclaration AddHardwiredFunction(
string name,
Module module,
TypeDefinition returnType,
params string[] parameters)
{
var res = new FunctionDeclaration(name, returnType, new Block(module.Block, module), parameters)
{
IsInternal = true
};
return(res);
}
/// <summary>
/// Create a score to create a best fit for a function given a parameter list.
/// </summary>
/// <param name="func">The function to check the parameters for</param>
/// <param name="parameters">The list of parameters</param>
/// <returns>A score (see remarks). In case of -1 no match is possible (see cases in code)</returns>
/// <remarks>
/// How the score is calculated:
/// * Start with a score of 0
/// * For each parameter
/// ** If IsVar and types match exactly --> +1000 (super match)
/// ** If ByValue and types match exactly --> + 1000 (only checked for simple types)
/// ** If ByValue and types are compatible (e.g. INTEGER can be assigned to REAL) --> +1
/// In the unlikely event of having more than 1000 parameters, this algorithm might fail.
/// </remarks>
private static int GenerateFunctionParameterScore(FunctionDeclaration func,
IReadOnlyList <CallParameter> parameters)
{
int paramNo = 0;
int score = 0;
var procParams = func.Block.Declarations.OfType <ProcedureParameterDeclaration>().ToArray();
if (parameters.Count != procParams.Length)
{
return(-1); // will never match
}
foreach (var procedureParameter in procParams)
{
if (procedureParameter.IsVar)
{
if (!GenerateVarParameterCount(parameters[paramNo], procedureParameter, ref score))
{
return(-1);
}
}
else if (procedureParameter.Type.Type.HasFlag(BaseTypes.Simple) &&
procedureParameter.Type.Name == parameters[paramNo].TypeName)
{
score += 1000;
}
else if (!procedureParameter.Type.IsAssignable(parameters[paramNo].TargetType))
{
return(-1);
}
else
{
score++; // match as assignable --> small increment
}
paramNo++;
}
return(score);
}
private void DeclareStandardFunctions()
{
foreach (var function in _hardwiredFunctions)
{
Block.Procedures.Add(FunctionDeclaration.AddHardwiredFunction(function.Name, this,
function.Type == null ? SimpleTypeDefinition.VoidType : Block.LookupType(function.Type),
function.ParameterTypes));
}
Assembly asm = null;
var sysAsm = Assembly.Load("Oberon0.System");
asm = sysAsm; // reached only if no exception
foreach (var type in asm.GetExportedTypes())
{
if (type.GetCustomAttribute <Oberon0LibraryAttribute>() != null)
{
LoadLibraryMembers(type);
}
}
}
#pragma warning disable CS3001 // Argument type is not CLS-compliant
private FunctionDeclaration LookupFunction(string procedureName, IToken token,
IReadOnlyList <CallParameter> callParameters)
#pragma warning restore CS3001 // Argument type is not CLS-compliant
{
var b = this;
FunctionDeclaration resFunc = null;
// try to find the function with the best match (score) (e.g. ABS(REAL) and ABS(INTEGER) share the same function name
// of not found on current block level, move up (until root) to find something appropriate.
int score = -1;
while (b != null)
{
var res = b.Procedures.Where(x => x.Name == procedureName);
foreach (var func in res)
{
int newScore = GenerateFunctionParameterScore(func, callParameters);
if (newScore <= score)
{
continue;
}
resFunc = func;
score = newScore;
}
if (score >= 0)
{
break; // found
}
b = b.Parent;
}
if (resFunc == null)
{
var parameterList = new List <ProcedureParameterDeclaration>(callParameters.Count);
int n = 0;
parameterList.AddRange(
callParameters.Select(
expression =>
new ProcedureParameterDeclaration("param_" + n++, this, expression.TargetType, false)));
string prototype = FunctionDeclaration.BuildPrototype(
procedureName,
SimpleTypeDefinition.VoidType,
parameterList.ToArray());
if (Module.CompilerInstance != null)
{
Module.CompilerInstance.Parser.NotifyErrorListeners(
token,
$"No procedure/function with prototype '{prototype}' found",
null);
}
else
{
throw new InvalidOperationException($"No procedure/function with prototype '{prototype}' found");
}
}
return(resFunc);
}