6.2.2405 VALUE CORE EXT

( x "<spaces>name" -- )

Skip leading space delimiters. Parse name delimited by a space. Create a definition for name with the execution semantics defined below, with an initial value equal to x.

name is referred to as a "value".

name Execution:

( -- x )

Place x on the stack. The value of x is that given when name was created, until the phrase x TO name is executed, causing a new value of x to be assigned to name.

TO name Run-time:

( x -- )

Assign the value x to name.

See:

3.4.1 Parsing, 6.2.2295 TO, A.6.2.2405 VALUE.

Rationale:

Typical use:

0 VALUE data

: EXCHANGE ( n1 -- n2 ) data SWAP TO data ;

EXCHANGE leaves n₁ in data and returns the prior value n₂.

Testing:

T{ 111 VALUE v1 -> }T
T{ -999 VALUE v2 -> }T
T{ v1 -> 111 }T
T{ v2 -> -999 }T
T{ 222 TO v1 -> }T
T{ v1 -> 222 }T

T{ : vd1 v1 ; -> }T
T{ vd1 -> 222 }T