symbolic function preparser bug

[williamstein]

sage: preparse('f(x) = x')
'_=var("x");f=symbolic_expression(x).function(x)'
sage: preparse('f(x) =+x')
'f(x) =+x'
sage: preparse('f(x) =-x')
'f(x) =-x'

This was found by Jason Grout, with input by Jaap Spies and John Cremona.

Component: calculus

Issue created by migration from https://trac.sagemath.org/ticket/1776

[williamstein]

slightly better fix (there is only one post-equals symbol, namely =). This also fixes typos and mistakes in some of the docs.

[jaapspies]

comment:2

Attachment: trac1776.patch.gz

Works for me!

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| SAGE Version 2.10.alpha2, Release Date: 2008-01-11                 |
| Type notebook() for the GUI, and license() for information.        |
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sage: f(x)=-x

sage: f(2)
 -2


Jaap

[sagetrac-mabshoff]

comment:4

Merged in Sage 2.10.alpha3.