Questions tagged [argument-patterns]
Questions concerning argument patterns used as formal arguments in function definitions (e.g., := expressions) to restrict the kinds of values that can be passed as actual arguments. Also questions about how such patterns can be used to achieve function overloading.
25
questions with no upvoted or accepted answers
8
votes
0
answers
74
views
Why does Longest not work on OptionsPattern?
When having a function with optional arguments and options, I frequently find myself writing something like this:
...
- 34k
7
votes
0
answers
165
views
Exceeding recursion limit with no obvious recursion: Optional pattern-matching causing nonlocal behavior
So, I've come across something strange, and wanted to get a deeper understanding of what was going on. Consider the following code:
...
- 9,010
6
votes
0
answers
119
views
Difference between the infinite rewriting behavior of evaluation and ReplaceRepeated
In the documentation tutorial/Evaluation it's said that:
Every time the expression changes, the Wolfram Language effectively starts the evaluation sequence over ...
- 573
6
votes
0
answers
366
views
About the OptionsPattern[] approach of inheriting Options
Szabolcs showed in this post, that there are possibly two approaches to inherit function options. He recommended the Join approach. At first, I agreed. But today I ...
- 17.1k
5
votes
0
answers
396
views
Syntax error for optional pattern, but only in debugger
This expression (explained here by Leonid) evaluates fine unless Evaluation->Debugger is enabled:
h[x : (_Integer) : 1] := x
Syntax::sntxf: "x:" cannot be ...
- 16.6k
4
votes
0
answers
114
views
Lint checker for overlapping or conflicting function signature patterns
In building a system like Mathics (or anything having the number of builtin functions of Mathematica) there are lots of function definitions. I would like to sanity check or lint check the pattern in ...
- 245
4
votes
0
answers
77
views
Preventing $-renaming of pattern names in lexically-scoped constructs
When you use a lexically-scoped construct like With or Function to perform replacements in an expression, Mathematica might ...
- 9,010
4
votes
0
answers
76
views
How to get f[x] to match with f[c_., x] when OneIdentity doesn't match
After setting:
SetAttributes[f, OneIdentity]
Default[f] = 1;
We have the following successful matches:
...
- 19.7k
2
votes
0
answers
335
views
How to test for arguments for a pattern that is of a positive Integer OR Infinity so that both filter through to the definition on RHS?
How can I filter an argument of a function so that definition works on positive Integers (y >= 0) or Infinity? It will ...
- 2,457
2
votes
0
answers
79
views
How to specify complicated patterns in function arguments?
Unfortunately, I have not found in documentation how to create complicated patterns in arguments of a function
Consider a toy example. Say, I would like to have a simple function
...
- 906
2
votes
0
answers
103
views
How does Mathematica choose which function definition to use?
I was wondering what the process of matching function arguments arguments against different function definitions actually looks like for Mathematica.
(Just to be clear, I'm not simply looking for an ...
- 9,010
2
votes
0
answers
95
views
Is there something like a function pattern test?
Is there something like a function pattern test?
function[x_?FunctionQ]:=Module[{},]
In order that Mathematica can tell if the argument is a function or a ...
- 2,192
2
votes
0
answers
111
views
Automating generation of argument error messages
You can run into messages like
DistributionFitTest["kk", "TestConclusion"]
...
- 5,739
1
vote
1
answer
94
views
How to define a mixed pattern consisting of string and regular patterns for function definition (using SetDelayed)?
I'm kinda stuck here, and I could really use some help:
I want to define a function, let's call it quarterValue, that accepts a ...
- 332
1
vote
0
answers
63
views
How conflicting patterns are resolved?
I often find myself doing something like this (probably poor example, sorry)
f[x_] := 0
f[x_Plus] := 1
In the back of my mind generally ...
- 535
1
vote
0
answers
39
views
Is there a way to get the calling information inside the body of a function defined using down value?
Suppose a function has multiple argument structure like follows:
...
- 9,385
1
vote
1
answer
118
views
Functions definitions with variable arguments
How do you define a variable amount of functions with a variable amount of arguments? I don't get the reference at all :
...
- 101
1
vote
0
answers
92
views
Using Two Arguments on the Same Function
I'm having some trouble wrapping my head around how I would go about using two arguments in one function. In the first section of the code below, I have scraped some "tweets" on the Seeking Alpha ...
- 647
1
vote
0
answers
59
views
Is there any point to using a variable as a function parameter?
Normally one only sees patterns as function parameters:
fun1[x_]:=x^2
Is there any point to using a variable in a function definition:
...
- 4,090
0
votes
0
answers
72
views
How to specify specific (custom) function arguments
Suppose that I want to have a function that is evaluated only when a user-specific, predefined flag is given out of a list of possible flags. For example
...
- 783
0
votes
0
answers
48
views
Detecting whether a function is initially defined with the form R[x,y] or R[x_,y_], etc
I have a very long code that may have errors in definition of functions and I want to trace these errors.
Is there any attribute or function to detect whether a function is initially defined in the ...
- 410
0
votes
0
answers
288
views
How to convert Symbol to Number?
Question
I have a variable x which is associated with the number 1 : x= 1
In the program, I faced with the data type problem ...
- 113
0
votes
0
answers
56
views
Head of complex sum
We have:
1 + 2 I + 3 + 4 I // Head
Complex
and
1 + 2 I + 3/5 + 4/5 I // Head
Complex
But we get:
...
- 11.9k
0
votes
0
answers
81
views
Delayed Rule right-hand-side mis-evaluation
Outline
I am trying to create a rule that will give me a minus sign if the number of times A is applied on X is odd where A is some οperator and X a random quantity.
Some of the configurations of ...
- 65
0
votes
0
answers
50
views
Defining functions with pattern as argument
I want to define a function such that
f[18/17 h[y][z]] = 18/17 z
for any function h[y][z].
I first tried with ...
- 1,648