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based on an earlier version of the Wolfram Language.
View current documentation (Version 11.2)


assigns rhs to be the delayed value of lhs, and associates the assignment with the symbol f.
An expression with a delayed definition is evaluated every time it is used:
Make definitions for special and general cases using immediate and delayed assignments:
The tag can appear as an argument of the left side:
The tag can appear as the head of an argument of the left side:
For ownvalues, the tag is redundant:
For downvalues, the tag is redundant:
Use a tag to define upvalues:
Implement modular arithmetic:
defines upvalues in the same way as using a tag does:
A tag defines only one upvalue; makes definitions for all symbols:
The right side of an immediate definition is evaluated when the definition is made:
The right side of a delayed definition is evaluated each time the definition is used:
Definitions with the same left side overwrite earlier ones:
Definition prints definitions associated with a symbol:
Information prints various information about a symbol, including any definitions:
UpValues returns a list of rules corresponding to any upvalues defined:
Use to clear definitions with a particular left-hand side:
Clear all definitions:
Delayed assignment introduces a scope that is not affected by global variables:
Immediate assignment does not introduce a scope:
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