Compatibility with newer nim

Author: yglukhov

nimsl.nimble

@@ -1,5 +1,5 @@
 # Package
-version = "0.3"
+version = "0.3.1"
 author = "Yuriy Glukhov"
 description = "Shaders in Nim"
 license = "MIT"

nimsl/private/glsl_codegen.nim

@@ -345,8 +345,13 @@ proc genWhileStmt(ctx: var GLSLCompilerContext, n: NimNode, r: var string) =
 proc genConv(ctx: var GLSLCompilerContext, n: NimNode, r: var string) =
     gen(ctx, n[1], r)
 
+proc skipConv(n: NimNode): NimNode =
+  result = n
+  while result.kind == nnkHiddenStdConv:
+    result = result[^1]
+
 proc genBracketExpr(ctx: var GLSLCompilerContext, n: NimNode, r: var string) =
-    let indexVal = n[1].intVal
+    let indexVal = n[1].skipConv.intVal
     gen(ctx, n[0], r)
     r &= "."
     case indexVal