[Wisp-cvs] wisp/users/dig tran.py,1.28,1.29

[<di...@us...>]

Update of /cvsroot/wisp/wisp/users/dig
In directory sc8-pr-cvs1:/tmp/cvs-serv10060

Modified Files:
	tran.py 
Log Message:
better literal arithmetics

Index: tran.py
===================================================================
RCS file: /cvsroot/wisp/wisp/users/dig/tran.py,v
retrieving revision 1.28
retrieving revision 1.29
diff -u -d -r1.28 -r1.29
--- tran.py	17 Apr 2003 11:50:34 -0000	1.28
+++ tran.py	17 Apr 2003 12:17:14 -0000	1.29
@@ -35,6 +35,14 @@
         return str.__new__(cls, s)
     def __repr__ (this):
         return 'Symbol_Literal(%r)' % str(this)
+    def __add__ (this, that):
+        if not isinstance(this, Constant_Sum): this = Constant_Sum(this)
+        if not isinstance(that, Constant_Sum): that = Constant_Sum(that)
+        return this + that
+    def __sub__ (this, that):
+        if not isinstance(this, Constant_Sum): this = Constant_Sum(this)
+        if not isinstance(that, Constant_Sum): that = Constant_Sum(that)
+        return this - that
 
 class Unique:
     def __init__ (this, name):
@@ -51,6 +59,10 @@
 
 class Constant_Sum (Stackable):
     def __init__ (this, plus = (), minus = (), scalar = 0L):
+        if isinstance(plus, Symbol_Literal) or plus == Dollar or \
+                isinstance(plus, Integer_Literal): plus = plus,
+        if isinstance(minus, Symbol_Literal) or minus == Dollar or \
+                isinstance(minus, Integer_Literal): minus = minus,
         this.scalar = long(scalar)
         this.plus = []; this.minus = []
         for item in plus:
@@ -71,13 +83,13 @@
             that = Constant_Sum(plus = [that])
         return Constant_Sum(plus = this.plus + that.plus,
                             minus = this.minus + that.minus,
-                            scalar = this.scalar + that.scalar)
+                            scalar = this.scalar + that.scalar).simplify()
     def __sub__ (this, that):
         if isinstance(that, Symbol_Literal) or that == Dollar:
             that = Constant_Sum(plus = [that])
         return Constant_Sum(plus = this.plus + that.minus,
                             minus = this.minus + that.plus,
-                            scalar = this.scalar - that.scalar)
+                            scalar = this.scalar - that.scalar).simplify()
     def __repr__ (this):
         arg = []
         if this.plus: arg.append('plus = ' + `this.plus`)
@@ -93,6 +105,12 @@
         if res[0] == ' ': res = res[1:]
         if res[:2] == '+ ': res = res[2:]
         return '(' + res + ')'
+    def simplify (this):
+        if len(this.plus) == 0 and len(this.minus) == 0:
+            return Integer_Literal(this.scalar)
+        if len(this.plus) == 1 and len(this.minus) == 0 and this.scalar == 0:
+            return this.plus[0]
+        else: return this
 
 class Lexer (shlex):
     def __init__ (this, filename):