expr.spad line 972 [edit on github]
Attaching assertions to symbols for pattern matching; Date Created: 21 Mar 1989
constant(x)
tells the pattern matcher that x
should match only the symbol 'x
and no other quantity. Error: if x
is not a symbol.
multiple(x)
tells the pattern matcher that x
should preferably match a multi-term quantity in a sum or product. For matching on lists, multiple(x
) tells the pattern matcher that x
should match a list instead of an element of a list. Error: if x
is not a symbol.
optional(x)
tells the pattern matcher that x
can match an identity (0 in a sum, 1 in a product or exponentiation). Error: if x
is not a symbol.