Questions on Mathematica's scoping constructs (Block, Module, With, etc.)

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2
votes
1answer
110 views

Module Inside ToBoxes or MakeBoxes

Does someone mind explaining why Module doesn't seem to work while inside ToBoxes or MakeBoxes. ...
1
vote
2answers
149 views

Confused about scoping, not sure what to ask

I'm grading for a class using Mathematica right now, and one of the students ran into a weird issue. When he ran code like this: ...
6
votes
1answer
123 views

Creating a Block from a list of rules

How can I create a function which works like Block but takes a list of rules as its first argument, rather than a list of assignments? The function needs to be ...
12
votes
3answers
287 views

Variable scope similar to other languages

Mathematica, unlike many other languages, defines the variables in the global scope unless it is explicitly asked to define a variable in a local scope, e.g., using ...
7
votes
0answers
233 views

Compile recursive function modifying global variables

How to compile recursive formula when it relies on more than a few global variables (global to the topmost compiled function)? It is unreasonable to pass on all such variables to each recursive ...
0
votes
1answer
92 views

Arbitrary number of variables in Module, Block, etc

How do I specify an arbitrary number of variable names and initialize them inside of a Module or Block? For example, I want to do something like: ...
0
votes
1answer
76 views

Scope of expression in a user-defined function

I have the following code: fbasic = A + R + Z*Z *Z*Z; f[A_, Z_, R_] := fbasic + R; f[0, 2, 3] The answer I am getting is ...
7
votes
3answers
445 views

What is the right way to construct DynamicModule

When I'm creating DynamicModules for CDF purposes I'm usualy basing on my experience with that, particular goal and content rather than on deep insight. I want to ...
2
votes
1answer
235 views

Call Functions From File Without Modifying Context (Sandbox)

Let's say I have file named test.m containing test[arg1_] := ( Print[arg1];) What is the best technique for calling test like ...
1
vote
0answers
110 views

Variable scope in nested NMaximize, NMaxValue

I'm trying to use NMaxValue inside other statements (FindRoot and NMinimize). Those statements should bind variable names, but I'm getting weird warnings which seem to indicate that the variables ...
0
votes
1answer
204 views

Why the dollar signs when I Solve inside a Module [closed]

I would like the solutions of my equations to be local only, so I did a Solve inside a Module: Module[{a, b, c}, Solve[{a == 3* c, b == 2 *a}, {a, b}]] and the ...
9
votes
1answer
120 views

What are the scoping rules for function parameters shadowing System` symbols?

Here are some very contrived code snippets, highly unlikely to appear in real code, but still I am curious why they behave like this: ...
5
votes
0answers
111 views

Are there any videos that show how different Mathematica expressions are evaluated?

Are there any videos that show how different Mathematica expressions are represented internally as object graphs and demonstrate how they are transformed during an evaluation? I am asking because I ...
0
votes
2answers
223 views

Why does my code return {Null, Null, Null}? [closed]

I have a module created which makes what I want, but at the end there are {NULL, NULL, NULL}. Why that? How can I prevent this NULL list? ...
8
votes
1answer
132 views

Is it possible to write a function immune to symbol redefinitions in any Block surrounding its invocation?

Normally, semantics of symbols used in a function definition can be changed by their redefinitions in Blocks surrounding the function invocation: ...
3
votes
1answer
138 views

Issue with scope of variables

For the definitions, t = 1; f[x_, y_] := t (x + y); v[3] := {1, 1}; g[u_] := f[v[u][[1]], v[u][[2]]]; the following two expressions yield different results, ...
8
votes
1answer
120 views

Is it possible to use the global definition of a symbol as part of its new local definition set in a Block?

Consider the following expression: Block[{Print = CopyToClipboard}, doSomething[]] Now all calls to Print from ...
2
votes
1answer
129 views

Effect of Block[] on iterators in Manipulate[]

The following is a toy example that hopefully shows the problem clearly enough. Why does the following code create a nice, manipulable output: ...
7
votes
1answer
161 views

FullDefinition and Module local variable

I have a question about FullDefinition and how it interacts with the local variables of Module. I've created a few functions ...
2
votes
1answer
123 views

Odd edge-case behavior of Block

In this example, Block is used to localize the variable cache as used in the function g when called from the function ...
3
votes
1answer
142 views

How can I set multiple values to local variables in a Module?

Multiple assignment is supported by Set. How can do something similar in Module expressions? If I could do it, whould there be ...
23
votes
1answer
217 views

What does Internal`InheritedBlock do?

What does the function Internal`InheritedBlock do? How is it different from the regular Block?
4
votes
3answers
145 views

Modify this code using Module and While

I have written a recursive function and would like to re-write the code using Module AND While to compare the timings. Here is my recursive function for f[n], where 6 n f[n] = f[n-1] + n! for n>0 and ...
6
votes
2answers
192 views

Variable scoping problem when mapping over delayed replacement

This is something that got me curious while I was playing around with Mathematica. Consider the following (contrived) example: ...
9
votes
0answers
142 views

Compile not correctly initializing a variable defined inside Module

In the following example, inside the minimumX's Module, x is initialized to 1, but the ...
0
votes
1answer
59 views

Don't pollute outside context when solving equation from the outside

This code works fine only if a is not defined in the outside context: ...
2
votes
1answer
81 views

How to make a code line dynamic in a Module?

The code line If[StreamPosition>0,Read[str,Record]] should be executed in a Module at first. The Module consists of a Slider and a Pane. The Slider ...
7
votes
3answers
240 views

How do I avoid scoping collisions of iterator variables?

Yesterday I had an issue that kept for quite a while. My code wasn't producing the right results. Now I know why and I am wondering how to avoid the issue in future. Consider the following code. ...
3
votes
3answers
323 views

Defining a new Function using RegionPlot

I'm trying to make images like this: to illustrate 2D integrals to a calculus class. I used the code ...
8
votes
2answers
146 views

Possible to scope an anonymous function within Module?

This is my first question. I'm fairly new to Mathematica and completely new to SE, so I apologize if this question is trivial. I'm working on a problem that requires a function to be redefined ...
22
votes
4answers
431 views

Enforcing correct variable bindings and avoiding renamings for conflicting variables in nested scoping constructs

Using global variables the following turns an "expression" into a Function: expr = 2 x; Function[x, Evaluate[expr]] Of course ...
5
votes
1answer
1k views

Module with “local functions”

I am trying to use a Module having "local functions", i.e., those which I need to define only inside this module. So I tried this: ...
3
votes
1answer
134 views

Downvalues vs. Scoping for Functions

Regarding my recent question on using a default value for a function argument when a pattern was not met yielded some interesting answers, but the general consensus was "Yes this can be done, but ...
3
votes
2answers
217 views

Why does the syntax highlighter color a local symbol red inside DynamicModule?

I am adding a Module inside DynamicModule here is an example (thanks to @rm-rf for this simple example) ...
14
votes
1answer
269 views

Is the sharing of variables in Module/Block within Compile documented behavior?

Today I noticed something, I think for the first time. When used inside Compile variable values within Module (and ...
7
votes
4answers
379 views

How to set Block local variables by code?

I need to create a user defined Block function where the Block variables values are defined by code. For example, imagine I have: ...
18
votes
1answer
200 views

“With” as part of the “Dynamic Interactivity Language”

I noticed that in Mathematica's Function Navigator With is listed as being part of the "Dynamic Interactivity Language". It is not the first (or even the fourth, ...
7
votes
2answers
148 views

How to define UpValues in a different context from within a package

I'm trying to create a function (in a package) to import a lot of data and create a symbol with UpValues to return specific results about the data. I've got it working fine in a regular notebook, but ...
0
votes
0answers
67 views

What's the best practice for nested local constants? [duplicate]

Possible Duplicate: How to avoid nested With[]? I have many situations where I have a constant that is local to a function, with other constants that are computed from it. I see that I can ...
9
votes
2answers
257 views

Localizing variables within a Manipulate

I have a notebook with several examples of very similar computations, each involving the same variable/parameter names of the ingredients used in a final ...
12
votes
1answer
273 views

Modules that initialize themselves on first call

I use a lot of functions that extract a specific data item from a file with many data items. I want these functions to load data (slow) and return the item (fast) on first call, but just return the ...
19
votes
2answers
747 views

What are some advanced uses for Block?

I read the answer to this question and this one. According to those, Block is safer (if something aborts, it restores the values) and faster (perhaps something to ...
3
votes
2answers
245 views

LetL and Module efficiency

I was recently introduced to the LetL macro thanks to Leonid's answer to one of my prior questions. I was, needless to say, impressed by the simplicity of its ...
32
votes
4answers
756 views

How to avoid nested With[]?

With[ {v1 = #}, With[ {v2 = f[v1]}, g[v1, v2] ] ] How to avoid nested With[] like the above? I'd like to use ...
0
votes
1answer
129 views
0
votes
3answers
349 views

Constructing a list with a Module [closed]

I have build this simple module trying to construct a matrix via Table ...
9
votes
2answers
225 views

Strange results while nesting scope constructs?

I did a handful of tests with Block, With, and Module and had a couple of new surprises. ...
5
votes
1answer
227 views

Parts of Module body evaluated in external scope?

I have an expression that suggests that some expressions in a module body are dragging in definitions from outside the scope in a surprising way. First, consider a symbolic constant, ...
1
vote
1answer
172 views

Using block or module to free cache

I'm writing some code at the moment that schematically looks like: (set initial conditions for some differential equation for given parameters (M,R,...)) ...
34
votes
3answers
995 views

Why modules with no variables?

I was reading some code, in particular, recipe 4.13 on unification pattern-matching in Sal Mangano's Mathematica Cookbook, and there were many instances of Modules with no variables in them, such as ...