411 REFERENCE · Wikibooks
Rebol Programming/assert
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
USAGE:
ASSERT conditions /type
DESCRIPTION:
Assert that condition is true, else throw an assertion error.
ASSERT is a function value.
ARGUMENTS
conditions -- (Type: block)
REFINEMENTS
/type -- Safely check datatypes of variables (words)
(SPECIAL ATTRIBUTES)
catch
throw
SOURCE CODE
assert: func [
{Assert that condition is true, else throw an assertion error.}
[catch throw]
conditions [block!]
/type "Safely check datatypes of variables (words)"
/local w t
][throw-on-error [
either type [
parse conditions [any [
[set w word! | set w skip (
cause-error 'script 'invalid-arg type? get/any 'w
)]
[set t [block! | word!] (
unless find to-typeset t type? get/any w [
make error! join "datatype assertion failed for: " w
]
) | set t skip (
cause-error 'script 'invalid-arg type? get/any 't
)]
]]
] [
any [
all conditions
make error! join "assertion failed for: " mold conditions
]
]
]]