/// <summary>
/// Look up a value in this dictionary, walking the __isa chain to find
/// it in a parent object if necessary; return both the value found an
/// (via the output parameter) the map it was found in.
/// </summary>
/// <param name="key">key to search for</param>
/// <returns>value associated with that key, or null if not found</returns>
public Value Lookup(Value key, out ValMap valueFoundIn)
{
if (key == null)
{
key = ValNull.instance;
}
Value result = null;
ValMap obj = this;
while (obj != null)
{
if (obj.TryGetValue(key, out result))
{
valueFoundIn = obj;
return(result);
}
Value parent;
if (!obj.TryGetValue(ValString.magicIsA, out parent))
{
break;
}
obj = parent as ValMap;
}
valueFoundIn = null;
return(null);
}
/// <summary>
/// Get the value of a local variable ONLY -- does not check any other
/// scopes, nor check for special built-in identifiers like "globals".
/// Used mainly by host apps to easily look up an argument to an
/// intrinsic function call by the parameter name.
/// </summary>
public Value GetLocal(string identifier, Value defaultValue = null)
{
Value result;
if (variables != null && variables.TryGetValue(identifier, out result))
{
return(result);
}
return(defaultValue);
}
/// <summary>
/// Get the value of a variable available in this context (including
/// locals, globals, and intrinsics). Raise an exception if no such
/// identifier can be found.
/// </summary>
/// <param name="identifier">name of identifier to look up</param>
/// <returns>value of that identifier</returns>
public Value GetVar(string identifier)
{
// check for special built-in identifiers 'locals' and 'globals'
if (identifier == "locals")
{
if (variables == null)
{
variables = new ValMap();
}
return(variables);
}
if (identifier == "globals")
{
if (root.variables == null)
{
root.variables = new ValMap();
}
return(root.variables);
}
// check for a local variable
Value result;
if (variables != null && variables.TryGetValue(identifier, out result))
{
return(result);
}
// OK, we don't have a local variable with that name.
// Check higher scopes.
Context c = parent;
while (c != null)
{
if (c.variables != null && c.variables.ContainsKey(identifier))
{
return(c.variables[identifier]);
}
c = c.parent;
}
// Finally, check intrinsics.
Intrinsic intrinsic = Intrinsic.GetByName(identifier);
if (intrinsic != null)
{
return(intrinsic.GetFunc());
}
// No luck there either? Undefined identifier.
throw new UndefinedIdentifierException(identifier);
}
/// <summary>
/// Get the value of a variable available in this context (including
/// locals, globals, and intrinsics). Raise an exception if no such
/// identifier can be found.
/// </summary>
/// <param name="identifier">name of identifier to look up</param>
/// <returns>value of that identifier</returns>
public Value GetVar(string identifier)
{
// check for special built-in identifiers 'locals' and 'globals'
if (identifier == "locals")
{
if (variables == null)
{
variables = ValMap.Create();
}
return(variables);
}
if (identifier == "globals")
{
if (root.variables == null)
{
root.variables = ValMap.Create();
}
return(root.variables);
}
if (identifier == "outer")
{
// return module variables, if we have them; else globals
if (outerVars != null)
{
return(outerVars);
}
if (root.variables == null)
{
root.variables = ValMap.Create();
}
return(root.variables);
}
// check for a local variable
Value result;
if (variables != null && variables.TryGetValue(identifier, out result))
{
return(result);
}
// check for a module variable
if (outerVars != null && outerVars.TryGetValue(identifier, out result))
{
return(result);
}
// OK, we don't have a local or module variable with that name.
// Check the global scope (if that's not us already).
if (parent != null)
{
Context globals = root;
if (globals.variables != null && globals.variables.ContainsKey(identifier))
{
return(globals.variables[identifier]);
}
}
// Finally, check intrinsics.
Intrinsic intrinsic = Intrinsic.GetByName(identifier);
if (intrinsic != null)
{
return(intrinsic.GetFunc());
}
// No luck there either? Undefined identifier.
throw new UndefinedIdentifierException(identifier);
}
/// <summary>
/// Look up the given identifier in the given sequence, walking the type chain
/// until we either find it, or fail.
/// </summary>
/// <param name="sequence">Sequence (object) to look in.</param>
/// <param name="identifier">Identifier to look for.</param>
/// <param name="context">Context.</param>
public static Value Resolve(Value sequence, string identifier, Context context, out ValMap valueFoundIn)
{
var includeMapType = true;
valueFoundIn = null;
int loopsLeft = 1000; // (max __isa chain depth)
while (sequence != null)
{
int seqTypeInt = sequence.GetBaseMiniscriptType();
//if (sequence is ValTemp || sequence is ValVar)
if (seqTypeInt == MiniscriptTypeInts.ValTempTypeInt || seqTypeInt == MiniscriptTypeInts.ValVarTypeInt)
{
sequence = sequence.Val(context, false);
seqTypeInt = sequence == null ? -1 : sequence.GetBaseMiniscriptType();
}
//if (sequence is ValMap) {
if (seqTypeInt == MiniscriptTypeInts.ValMapTypeInt)
{
// If the map contains this identifier, return its value.
ValMap seqMap = sequence as ValMap;
Value result = null;
var idVal = ValString.Create(identifier);
bool found = seqMap.TryGetValue(idVal, out result);
idVal.Unref();
if (found)
{
valueFoundIn = seqMap;
return(result);
}
// Otherwise, if we have an __isa, try that next.
if (loopsLeft < 0)
{
return(null); // (unless we've hit the loop limit)
}
if (!seqMap.TryGetValue(ValString.magicIsA, out sequence))
{
// ...and if we don't have an __isa, try the generic map type if allowed
if (!includeMapType)
{
throw new KeyException(identifier);
}
sequence = context.vm.mapType ?? Intrinsics.MapType();
includeMapType = false;
}
//} else if (sequence is ValList) {
}
else if (seqTypeInt == MiniscriptTypeInts.ValListTypeInt)
{
sequence = context.vm.listType ?? Intrinsics.ListType();
includeMapType = false;
//} else if (sequence is ValString) {
}
else if (seqTypeInt == MiniscriptTypeInts.ValStringTypeInt)
{
sequence = context.vm.stringType ?? Intrinsics.StringType();
includeMapType = false;
//} else if (sequence is ValNumber) {
}
else if (seqTypeInt == MiniscriptTypeInts.ValNumberTypeInt)
{
sequence = context.vm.numberType ?? Intrinsics.NumberType();
includeMapType = false;
//} else if (sequence is ValFunction) {
}
else if (seqTypeInt == MiniscriptTypeInts.ValFunctionTypeInt)
{
sequence = context.vm.functionType ?? Intrinsics.FunctionType();
includeMapType = false;
}
else if (seqTypeInt == MiniscriptTypeInts.ValCustomTypeInt)
{
ValCustom custom = sequence as ValCustom;
if (custom.Resolve(identifier, out Value result))
{
//valueFoundIn
return(result);
}
return(null);
}
else
{
throw new TypeException("Type Error (while attempting to look up " + identifier + ")");
}
loopsLeft--;
}
return(null);
}
