//Generate the Lookahed computation for a particular language definition
private static bool GenerateLookaheadExpr(LangDef def, StringBuilder sb, AlphabetDef aDef)
{
List<FastToken> children;
foreach (var ruleCase in def.cases)
{
children = ruleCase.pat.children;
sb.AppendLine("if(this.symbol==" + aDef.id.text + "." + ruleCase.pat.symbol + "){");
sb.Append("if(");
PrintExpr(children, ruleCase.where, sb);
sb.AppendLine("){");
#region Compute the given subsets
int childPos = 0;
string childName, langName;
HashSet<string>[] givenElelements = new HashSet<string>[children.Count];
for (int i = 0; i < givenElelements.Length; i++)
givenElelements[i] = new HashSet<string>();
#endregion
#region Populate given elements
foreach (var giv in ruleCase.given)
{
if (giv.kind == FExpKind.App)
{
langName = ((AppExp)giv).func.name.text;
childName = ((AppExp)giv).args[0].token.text;
childPos = 0;
foreach (var child in children)
{
if (child.text == childName)
break;
childPos++;
}
//Array of sets of langauges
if (!givenElelements[childPos].Contains(langName))
givenElelements[childPos].Add(langName);
}
}
#endregion
#region Compute lookahead
bool needsComma;
int givenUsed = 0;
for (int i = 0; i < givenElelements.Length; i++)
{
if (givenElelements[i].Count != 0)
{
sb.Append("if(this.children[" + i + "].langsLabel.IsSupersetOf(new string[] {");
needsComma = false;
foreach (var lang in givenElelements[i])
{
if (needsComma)
sb.Append(", ");
sb.Append("\"" + lang + "\"");
needsComma = true;
}
sb.Append("})){");
sb.AppendLine();
givenUsed++;
}
}
sb.AppendLine("this.langsLabel.Add(\"" + def.func.name.text + "\");");
#endregion
for (int i = 0; i < givenUsed; i++)
sb.AppendLine("}");
sb.AppendLine("}");
sb.AppendLine("}");
}
sb.AppendLine();
return true;
}
//Generate CSharp for languages
private static bool GenerateLanguage(LangDef def, StringBuilder sb)
{
sb.AppendLine("public bool " + def.func.name + "(){");
sb.AppendLine("return this.langsLabel.Contains(\""+def.func.name+"\");");
sb.AppendLine("}");
return true;
}
