From cc1b3ad0c3e2375bff3d0d736b988d41840dcadd Mon Sep 17 00:00:00 2001
From: dos-reis <gdr@axiomatics.org>
Date: Mon, 10 May 2010 02:32:04 +0000
Subject: 	Add lambda expression syntax to Boot. 	* boot/parser.boot
 (bpLambda): New. 	* boot/ast.boot (bfLambda): New. 	*
 boot/tokens.boot: Add "+->" as token. 	* interp/cparse.boot: Use lambda
 expression syntax. 	* interp/c-util.boot: Likewise.

---
 src/boot/parser.boot | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'src/boot/parser.boot')

diff --git a/src/boot/parser.boot b/src/boot/parser.boot
index ce22eb37..e754375d 100644
--- a/src/boot/parser.boot
+++ b/src/boot/parser.boot
@@ -800,6 +800,9 @@ bpAssign()==
     bpEqPeek "BEC" =>
       bpRestore a
       bpAssignment() or bpTrap()
+    bpEqPeek "GIVES" =>
+      bpRestore a
+      bpLambda() or bpTrap()
     true
   bpRestore a
   false
@@ -810,6 +813,14 @@ bpAssignment()==
       (bpAssign() or bpTrap()) and
 	 bpPush bfAssign (bpPop2(),bpPop1())
  
+++ Parse a lambda expression
+++   Lambda ::= Variable +-> Assign
+bpLambda() ==
+  bpVariable() and
+    bpEqKey "GIVES" and
+      (bpAssign() or bpTrap()) and
+        bpPush bfLambda(bpPop2(),bpPop1())
+
 -- should only be allowed in sequences
 bpExit()==
   bpAssign() and (bpEqKey "EXIT" and
-- 
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