[pypy-svn] r25301 - pypy/dist/pypy/objspace/logic

[auc at codespeak.net]

Author: auc
Date: Tue Apr  4 17:06:47 2006
New Revision: 25301

Added:
   pypy/dist/pypy/objspace/logic/syntax_proposal.py
Log:
discussion around syntax for logic variables


Added: pypy/dist/pypy/objspace/logic/syntax_proposal.py
==============================================================================
--- (empty file)
+++ pypy/dist/pypy/objspace/logic/syntax_proposal.py	Tue Apr  4 17:06:47 2006
@@ -0,0 +1,93 @@
+def foo_explicit(x,y):
+    """straightforward version. Just a new builtin to add The name of
+    the builtin can be discussed (current implementation uses
+    'newvar')
+    """
+    X = logicvar()
+    Y = logicvar()
+    unify(X, x)
+    unify(Y, y)
+    return X+Y
+
+
+def foo_let(x, y):
+    """requires adding a new node in the AST
+    the scoping rules need to be clarified
+    """
+    let X, Y:
+        unify(X, x)
+        unify(Y, y)
+        xx = X
+        return X+Y
+    print X #-> raises name error
+    print xx # no NameError (?)
+
+def foo_logic_kw(x,y):
+    """needs a new keyword
+    the logic keyword does not introduce a new scope (compare with let above)"""
+    logic X,Y 
+    unify(X, x)
+    unify(Y, y)
+    return X+Y
+
+def foo_with(x,y):
+    """requires python 2.5
+    we need logic to be a built in context manager
+    scoping rules are those of with"""
+    with logic(X, Y):
+        unify(X, x)
+        unify(Y, y)
+        return X+Y
+    print X #-> raises name error ???    
+    
+ at logic('X','Y')
+def foo_decorator(x,y):
+    """can this work at all ? The decorator would add local variables
+    to the function with the provided names, initialized as logic
+    variable"""
+    unify(X, x)
+    unify(Y, y)
+    return X+Y
+
+
+def foo_question_mark(x,y):
+    """introduce a new symbol '?'
+    """
+    X, Y = ?, ?
+    unify(X, x)
+    unify(Y, y)
+    return X+Y
+
+def foo_singleton(x,y):
+    """similar to foo_question_mark, but Unknown can clash with
+    existing code, and is longer to type"""
+    X, Y = Unknown, Unknown
+    unify(X, x)
+    unify(Y, y)
+    return X+Y
+
+def foo_equal_question_mark(x,y):
+    """introduces a new token '=?' without a right hand part
+    """
+    X, Y =?
+    unify(X, x)
+    unify(Y, y)
+    return X+Y
+
+
+def foo_visual_basic(x,y):
+    """for completeness, april fool was just a few days ago, please
+    bear with us"""
+    Dim X, Y as LogicalVariables
+    unify(X, x)
+    unify(Y, y)
+    return X+Y
+
+def foo_strange_question_mark(x,y): # ?????
+    """semantics are not totally clear yet, and auc feels this is not
+    going to match real life use cases. """
+    x = ?W
+    ?Z
+    unify(?X, x)
+    unify(?Y, y)
+    return ?X + ?Y