#14231: warn when preparser redefines Python builtin function
-------------------------------------------------------+--------------------
Reporter: ddrake | Owner: was
Type: enhancement | Status: new
Priority: major | Milestone:
sage-5.8
Component: user interface | Resolution:
Keywords: symbolic preparser builtin built-in | Work issues:
Report Upstream: N/A | Reviewers:
Authors: Dan Drake | Merged in:
Dependencies: | Stopgaps:
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Comment (by nbruin):
How about the list:
{{{
__builtin__.__dict__.keys()
}}}
If the problem is detected you could insert a warning printing message
into the preparsing result. Then the warning printing gets executed
together with the symbol binding.
The real problem here is that previously mistyping `len(t)==4` as
`len(t)=4` resulted in invalid syntax, whereas now it results in an
assignment. The same surprise happens when someone types
{{{
t = 0
sin(t) = 0 # mistyping of sin(t) == 0
}}}
Do you want to guard against that as well? Then quickly the whole
`f(t)=...` notation should lead to a warning (which I wouldn't mind
because I think it's one of the places where the preprocessor is too
intrusive)
In fact, always printing:
{{{
sage: f(u,v)=u+v
Defining symbolic function f and symbolic variables u,v
}}}
might not be so bad. We're defining new syntax. We can define new
semantics for that syntax, right?
We could have that result by ensuring that
{{{
sage: preparse('f(u,v)=u+v')
'__tmp__=var("u,v"); f = symbolic_expression(u+v).function(u,v); print
"Defining f and u,v"'
}}}
or whatever (terse) message would be reasonable.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/14231#comment:3>
Sage <http://www.sagemath.org>
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