object EvaluateWhereClause(Runtime.PassiveExpression expr, Runtime.Pattern lastPattern, ScriptThread thread)
{
// instantiate where-clause pattern
var patt = Pattern.Instantiate(thread);
patt.CopyBoundVariables(lastPattern);
// perform matching
var result = patt.Match(expr);
if (result)
{
// store last recognized pattern as a local variable
thread.SetLastPattern(patt);
// match succeeded, return result expression
if (ResultExpression != null)
{
return(ResultExpression.Evaluate(thread));
}
// match succeeded, evaluate more conditions
if (MoreConditions != null)
{
return(MoreConditions.Evaluate(thread));
}
}
// matching failed, return nothing
return(null);
}
void EvaluateWhereClause(Runtime.Pattern lastPattern, EvaluationContext context, AstMode mode)
{
// instantiate where-clause pattern
var patt = Pattern.Instantiate(context, mode);
patt.CopyBoundVariables(lastPattern);
// perform matching
var expr = context.Data.Pop() as Runtime.PassiveExpression;
var result = patt.Match(expr);
if (result)
{
// store last recognized pattern as a local variable
context.SetLastPattern(patt);
// match succeeded, return true
if (ResultExpression != null)
{
ResultExpression.Evaluate(context, AstMode.Read);
context.Data.Push(true);
return;
}
// match succeeded? depends on more conditions
if (MoreConditions != null)
{
// return true or false
MoreConditions.Evaluate(context, AstMode.Read);
return;
}
}
// match failed, return false
context.Data.Push(false);
}
