Wolfram Function Repository

Instant-use add-on functions for the Wolfram Language

Function Repository Resource:

 CompoundScope

Source Notebook

Scope with compounding expressions

Contributed by: Nikolay Murzin

ResourceFunction["CompoundScope"][{x=x0,y=y0,…},expr]

specifies that all occurences of the symbols x,y,… in expr should be replaced by values x0,y0,… where each value can depend on all the previous values.

ResourceFunction["CompoundScope"][{x=x0,code,y=y0,…},expr]

also evaluates code that may depend on previously assigned values.

ResourceFunction["CompoundScope"][x=x0;code;y=y0;…,expr]

is the same as ResourceFunction["CompoundScope"][{x=x0,code,y=y0,…},expr].

ResourceFunction["CompoundScope"][scope,assignments,expr]

applies a different scoping construct scope, which can be either With,Block or Module.

Details

ResourceFunction["CompoundScope"][values,expr] is equivalent to ResourceFunction["CompoundScope"][With,values,expr].
ResourceFunction["CompoundScope"] recursively uses the specified scoping construct for each individual value assignment.

Examples

Basic Examples (2) 

Evaluate an expression with x locally set to 7 and y to its square:

In[1]:=
ResourceFunction["CompoundScope"][{x = 7, y = x^2}, x + y]
Out[1]=

Echo an intermediate assigned value:

In[2]:=
ResourceFunction["CompoundScope"][{x = 7, Echo[x], y = x^2}, x + y]
Out[2]=

Scope (2) 

Use CompoundExpression instead of a List to separate assignments:

In[3]:=
ResourceFunction["CompoundScope"][x = 7; y = x^2, Hold[x + y]]
Out[3]=

Use different scoping functions:

In[4]:=
ResourceFunction["CompoundScope"][Block, {x = 7, y = x^2}, Hold[Evaluate[x], Evaluate[y], x + y]]
Out[4]=

Using Module introduces module variables:

In[5]:=
ResourceFunction["CompoundScope"][Module, {x = 7, y = x^2}, Hold[Evaluate[x], Evaluate[y], x + y]]
Out[5]=

Properties and Relations (2) 

Standard scoping constructs do not allow values to depend on previously assigned values:

In[6]:=
With[{x = 7, y = x^2}, Hold[x + y]]
Out[6]=

CompoundScope does compound assignments:

In[7]:=
ResourceFunction["CompoundScope"][{x = 7, y = x^2}, Hold[x + y]]
Out[7]=

Version History

  • 1.0.0 – 25 October 2022

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