match ( value1 value2 -- bindings )
Pattern matching

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Next:	match-cond ( assoc -- quot )

Vocabulary
match

Inputs

value1	an object
value2	an object

Outputs

bindings

an assoc

Word description
Pattern match value1 against value2. These values can be any Factor value, including sequences and tuples. The values can contain pattern variables, which are symbols that begin with '?'. The result is a hashtable of the bindings, mapping the pattern variables from one sequence to the equivalent value in the other sequence. The _ symbol can be used to ignore the value at that point in the pattern for the match.

Examples

USE: match MATCH-VARS: ?a ?b ; { ?a { 2 ?b } 5 } { 1 { 2 3 } _ } match .
H{ { ?a 1 } { ?b 3 } }

See also
match-cond, MATCH-VARS:, replace-patterns, match-replace

Definition

USING: kernel make ;

IN: match

: match ( value1 value2 -- bindings )
    [ (match) ] H{ } make swap [ drop f ] unless ;