substitute_function should not evaluate expression

[rwst]

One expects substitute_function to not do anything except exchanging parts of expressions but

sage: ex = sin(x) + atan2(0,0,hold=True) 
sage: ex.substitute_function(sin,cos)
...
RuntimeError: arctan2_eval(): arctan2(0,0) encountered
sage: ex = sin(x) + hypergeometric([1, 1], [2], -1)
sage: ex
hypergeometric((1, 1), (2,), -1) + sin(x)
sage: ex.substitute_function(sin,cos)              
AttributeError: 'SubstituteFunction' object has no attribute 'tuple'

Depends on #17759

Component: symbolics

Author: Ralf Stephan

Branch/Commit: c8ebd30

Reviewer: Marc Mezzarobba

Issue created by migration from https://trac.sagemath.org/ticket/17849

[rwst]

Dependencies: #17759

[rwst]

comment:2

Calling operator(*map(self, ex.operands()), hold=True) as a quick fix in SubstituteFunction.composition presupposes that all operators accept the keyword.

[rwst]

Branch: u/rws/substitute_function_should_not_evaluate_expression

[rwst]

Author: Ralf Stephan

[rwst]

New commits:

3781eec	17759: convenience class symbolic ExpressionTreeWalker(Converter)
9375510	Merge branch 'develop' into t/17759/public/17759
16aa81d	17759: handle hold=True and hypergeometric
d8767cd	Merge branch 'public/17759' of trac.sagemath.org:sage into t/17849/substitute_function_should_not_evaluate_expression
82332bb	17849: adapt SubstituteFunction; add doctest

[rwst]

Commit: 82332bb

[rwst]

Changed branch from u/rws/substitute_function_should_not_evaluate_expression to u/rws/17849

[rwst]

Changed branch from u/rws/17849 to u/rws/substitute_function_should_not_evaluate_expression