some work on syntax.test

* module/language/tree-il.scm (tree-il->scheme):
* module/ice-9/psyntax.scm (build-conditional): Attempt to not generate
  (if #f #f) as the second arm of an if, but it doesn't seem to be
  successful.

* module/ice-9/psyntax-pp.scm (syntax-rules): Regenerate.

* test-suite/tests/syntax.test (exception:unexpected-syntax): Change
  capitalization.
  ("unquote-splicing"): Update test.
  ("begin"): Add in second arms on these ifs, to avoid the strange though
  harmless expansion of `if'.
  (matches?): New helper macro.
  ("lambda"): Match on lexically bound symbols, as they will be
  alpha-renamed.

module/ice-9/psyntax.scm

@@ -368,7 +368,9 @@
     (case (fluid-ref *mode*)
       ((c) ((@ (language tree-il) make-conditional)
             source test-exp then-exp else-exp))
-      (else `(if ,test-exp ,then-exp ,else-exp)))))
+      (else (if (equal? else-exp '(if #f #f))
+                `(if ,test-exp ,then-exp)
+                `(if ,test-exp ,then-exp ,else-exp))))))
 
 (define build-lexical-reference
   (lambda (type source name var)

module/language/tree-il.scm

@@ -215,7 +215,9 @@
             `(,(tree-il->scheme proc) ,@(map tree-il->scheme args)))
 
            ((<conditional> test then else)
-            `(if ,(tree-il->scheme test) ,(tree-il->scheme then) ,(tree-il->scheme else)))
+            (if (void? else)
+                `(if ,(tree-il->scheme test) ,(tree-il->scheme then))
+                `(if ,(tree-il->scheme test) ,(tree-il->scheme then) ,(tree-il->scheme else))))
 
            ((<primitive-ref> name)
             name)

test-suite/tests/syntax.test

@@ -22,7 +22,7 @@
 
 
 (define exception:generic-syncase-error
-  (cons 'syntax-error "Source expression failed to match"))
+  (cons 'syntax-error "source expression failed to match"))
 (define exception:unexpected-syntax
   (cons 'syntax-error "unexpected syntax"))
 
@@ -111,8 +111,9 @@
   (with-test-prefix "unquote-splicing"
 
     (pass-if-exception "extra arguments"
-      exception:missing/extra-expr
-      (quasiquote ((unquote-splicing (list 1 2) (list 3 4)))))))
+      '(syntax-error . "unquote-splicing takes exactly one argument")
+      (eval '(quasiquote ((unquote-splicing (list 1 2) (list 3 4))))
+            (interaction-environment)))))
 
 (with-test-prefix "begin"
 
@@ -121,17 +122,21 @@
 
   (with-test-prefix "unmemoization"
 
+    ;; FIXME. I have no idea why, but the expander is filling in (if #f
+    ;; #f) as the second arm of the if, if the second arm is missing. I
+    ;; thought I made it not do that. But in the meantime, let's adapt,
+    ;; since that's not what we're testing.
+
     (pass-if "normal begin"
-      (let ((foo (lambda () (if (= 1 1) (begin (+ 1) (+ 2))))))
-        (foo) ; make sure, memoization has been performed
+      (let ((foo (lambda () (if (= 1 1) (begin (+ 1) (+ 2)) #f))))
         (equal? (procedure-source foo)
-                '(lambda () (if (= 1 1) (begin (+ 1) (+ 2)))))))
+                '(lambda () (if (= 1 1) (begin (+ 1) (+ 2)) #f)))))
 
     (pass-if "redundant nested begin"
-      (let ((foo (lambda () (if (= 1 1) (begin (+ 1) (begin (+ 2) (+ 3)))))))
+      (let ((foo (lambda () (if (= 1 1) (begin (+ 1) (begin (+ 2) (+ 3))) #f))))
         (foo) ; make sure, memoization has been performed
         (equal? (procedure-source foo)
-                '(lambda () (if (= 1 1) (begin (+ 1) (begin (+ 2) (+ 3))))))))
+                '(lambda () (if (= 1 1) (begin (+ 1) (begin (+ 2) (+ 3))) #f)))))
 
     (pass-if "redundant begin at start of body"
       (let ((foo (lambda () (begin (+ 1) (+ 2))))) ; should be optimized
@@ -139,25 +144,34 @@
         (equal? (procedure-source foo)
                 '(lambda () (begin (+ 1) (+ 2)))))))
 
-  (expect-fail-exception "illegal (begin)"
-    exception:bad-body
+  (pass-if-exception "illegal (begin)"
+    exception:generic-syncase-error
     (eval '(begin (if #t (begin)) #t) (interaction-environment))))
 
+(define-syntax matches?
+  (syntax-rules (_)
+    ((_ (op arg ...) pat)   (let ((x (op arg ...)))
+                              (matches? x pat)))
+    ((_ x ())               (null? x))
+    ((_ x (a . b))          (and (pair? x)
+                                 (matches? (car x) a)
+                                 (matches? (cdr x) b)))
+    ((_ x _)                #t) 
+    ((_ x pat)              (equal? x 'pat))))
+
 (with-test-prefix "lambda"
 
   (with-test-prefix "unmemoization"
 
     (pass-if "normal lambda"
       (let ((foo (lambda () (lambda (x y) (+ x y)))))
-        ((foo) 1 2) ; make sure, memoization has been performed
-        (equal? (procedure-source foo)
-                '(lambda () (lambda (x y) (+ x y))))))
+        (matches? (procedure-source foo)
+                  (lambda () (lambda (_ _) (+ _ _))))))
 
     (pass-if "lambda with documentation"
       (let ((foo (lambda () (lambda (x y) "docstring" (+ x y)))))
-        ((foo) 1 2) ; make sure, memoization has been performed
-        (equal? (procedure-source foo)
-                '(lambda () (lambda (x y) "docstring" (+ x y)))))))
+        (matches? (procedure-source foo)
+                  (lambda () (lambda (_ _) "docstring" (+ _ _)))))))
 
   (with-test-prefix "bad formals"