Add a compile-time loop construct to Slang

The basic syntax is:

    $for(i in Range(0,99))
    {
       /* stuff goes here */
    }

Note that the exact form is very restrictive. All that you are allowed to change is `i`, `0`, `99` or `/* stuff goes here */`.

As a tiny bit of syntax sugar, the following should work:

    $for(i in Range(99))
    {
       /* stuff goes here */
    }

Note that the range given is half-open (C++ iterator `[begin,end)` style).
Both the beginning and end of the range must be compile-time constant expressions that Slang knows how to constant-fold.

The implementation will basically generate code for `/* stuff goes here */` N times, once for each value in the half-open range.
Each time, the variable `i` will be replaced with a different compile-time-constant expression.

While I was working on a test case for this, I also found that our build of glslang had an issue with resource limits, so I fixed that.
Clients will need to build a new glslang to use the fix.

1 files changed, 10 insertions, 0 deletions

diff --git a/source/slang/stmt-defs.h b/source/slang/stmt-defs.h
index 9dea40fbf..80e3cd60d 100644
--- a/source/slang/stmt-defs.h
+++ b/source/slang/stmt-defs.h
@@ -96,6 +96,16 @@ SYNTAX_CLASS(DoWhileStatementSyntaxNode, LoopStmt)
     SYNTAX_FIELD(RefPtr<ExpressionSyntaxNode>, Predicate)
 END_SYNTAX_CLASS()
 
+// A compile-time, range-based `for` loop, which will not appear in the output code
+SYNTAX_CLASS(CompileTimeForStmt, ScopeStmt)
+    SYNTAX_FIELD(RefPtr<Variable>, varDecl)
+    SYNTAX_FIELD(RefPtr<ExpressionSyntaxNode>, rangeBeginExpr)
+    SYNTAX_FIELD(RefPtr<ExpressionSyntaxNode>, rangeEndExpr)
+    SYNTAX_FIELD(RefPtr<StatementSyntaxNode>, body)
+    SYNTAX_FIELD(RefPtr<IntVal>, rangeBeginVal)
+    SYNTAX_FIELD(RefPtr<IntVal>, rangeEndVal)
+END_SYNTAX_CLASS()
+
 // The case of child statements that do control flow relative
 // to their parent statement.
 ABSTRACT_SYNTAX_CLASS(JumpStmt, ChildStmt)