Extract discard expansion to a procedure.

1 files changed, 6 insertions, 3 deletions

diff --git a/chickadee/graphics/seagull.scm b/chickadee/graphics/seagull.scm
index ef6ec1f..11b38eb 100644
--- a/chickadee/graphics/seagull.scm
+++ b/chickadee/graphics/seagull.scm
@@ -521,6 +521,11 @@
                    (expand exp stage env)))
            names exps)))
 
+(define (expand:discard stage env)
+  (if (eq? stage 'fragment)
+      '(outputs)
+      (seagull-syntax-error "discard not allowed in vertex shader" exp expand)))
+
 (define (expand exp stage env)
   (define (primitive-call-for-stage? x)
     (primitive-call? x stage))
@@ -574,9 +579,7 @@
     (('case key clauses ...)
      (expand:case key clauses stage env))
     (('discard)
-     (if (eq? stage 'fragment)
-         '(outputs)
-         (seagull-syntax-error "discard not allowed in vertex shader" exp expand)))
+     (expand:discard stage env))
     ;; Primitive calls:
     (((? primitive-call-for-stage? operator) args ...)
      (expand:primitive-call operator args stage env))