VDM-10 Language Manual

Chapter 7
Patterns
Syntax: pattern bind = pattern | bind ;
pattern = pattern identifier
| match value
| set enum pattern
| set union pattern
| seq enum pattern
| seq conc pattern
| tuple pattern
| record pattern ;
pattern identifier = identifier | ‘-’ ;
match value = symbolic literal
| ‘(’, expression, ‘)’ ;
set enum pattern = ‘{’, [ pattern list], ‘}’ ;
set union pattern = pattern, ‘union’, pattern ;
seq enum pattern = ‘[’, [ pattern list], ‘]’ ;
seq conc pattern = pattern, ‘ˆ’, pattern ;
tuple pattern = ‘mk (’, pattern, ‘,’, pattern list, ‘)’ ;
record pattern = ‘mk ’, name, ‘(’, [ pattern list], ‘)’ ;
pattern list = pattern, { ‘,’, pattern } ;
73