Add support for unary minus operator

1 files changed, 9 insertions, 3 deletions

diff --git a/qklib/infix/rule-set.scm b/qklib/infix/rule-set.scm
index 1189bca..db0c4e5 100644
--- a/qklib/infix/rule-set.scm
+++ b/qklib/infix/rule-set.scm
@@ -34,6 +34,7 @@
           identity-value
           identity-inv?
           identity-unary?
+          identity-unary-precedence
 
           direction
           direction?
@@ -106,6 +107,9 @@
         ((symbol precedence direction identity)
          (operator symbol precedence direction identity #f))
         ((symbol precedence direction identity prefix)
+         (when (and identity (identity-unary? identity)
+                    (not (and direction (direction-left? direction))))
+           (error "operator: unary operator must be left direction" symbol))
          (make-operator symbol precedence direction identity prefix))))
 
     (define-record-type <direction>
@@ -160,14 +164,16 @@
          (make-prefix binary-only?  #t symbol))))
 
     (define-record-type <identity>
-      (make-identity value inv? unary?)
+      (make-identity value inv? unary? unary-precedence)
       identity?
       (value identity-value)
       (inv? identity-inv?)
-      (unary? identity-unary?))
+      (unary? identity-unary?)
+      (unary-precedence identity-unary-precedence))
 
     (define identity
       (case-lambda
         ((value) (identity value #f))
         ((value inv?) (identity value inv? #f))
-        ((value inv? unary?) (make-identity value inv? unary?))))))
+        ((value inv? unary?) (identity value inv? unary? #f))
+        ((value inv? unary? unary-precedence) (make-identity value inv? unary? unary-precedence))))))