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assert.fs (lib)

The assert.fs library contains words to add assertions to your code.


Simply write assertions in your code like this:

require assert.fs
1 assert-level! \ this is the default

: main
  assert( depth 0= )
  \ other code goes here...
  assert( 1 2 + 3 = ) ;

The code after the word assert( should push a flag to the parameter stack that indicates whether the assertion succeeded. The word ) consumes this flag and displays an error on false.

Make sure to not modify the stack in any other way between the assert( and ) words.

Assertion levels

The default assert-level is set to 1, which means that assertions defined with assert0( and assert1( are enabled. Other assertions (at level 2 and 3) will be skipped at compile-time and are not included in your final ROM.

The assert level can be set by calling assert-level! at toplevel. This value can not be modified at run-time.

Word Index

assert-level! ( u – )

Set the assertion level. Valid levels are 0, 1, 2, 3 (default is 1). Toplevel only, can not be used at run-time.

assert( ( – )

Alias for assert1(, the default assert.

assert0( ( – )

For important assertions that are always enabled.

assert1( ( – )

For regular assertions that are enabled by default.

assert2( ( – )

For debugging assertions that can be enabled manually.

assert3( ( – )

For extra slow assertions that can be enabled for thorough debugging.

) ( f – )

Ends the assertion. This word is doing the actual checking at run-time.