Morphett's FALSE

Implementation of programming language FALSE

An online interpreter created by Anthony Morphett. Is written in JavaScript. Differs from the original implementation in some details:

  • allows multi-character variable names (only lowercase alphabet letters are allowed). However, to stick to the language spirit it is recommended to use long names only if all single-letter names are already used.
  • a new rotate ® command is added which pops N from the stack and then moves S<N> to the top of the stack. This is done to fix the main inconvenience of the language — being unable to operate on stack elements except for top 3 ones.
  • input/output are not buffered, so flush ß is not implemented.
  • command-line arguments are not available.
  • inline-assembly command ` is not implemented; instead this character can be used to set breakpoints for debugging.

Morphett's FALSE interpreter (general appearance)
Morphett's FALSE interpreter (general appearance)

Links:

Examples:

Hello, World!:

Example for versions Morphett's FALSE

A string is equivalent to a command which simply prints it. There’s no way to put the string on the stack, except for as a part of a function. 

"Hello, World!"

Factorial:

Example for versions Morphett's FALSE

This example uses iterative method of factorial calculation. Variables i and f store current number (loop counter) and current factorial value. After the variables are initialized, the loop starts. [i;17=~] defines the continuation condition: as long as i doesn’t equal 17. Loop body follows: i and a string constant are printed, i is incremented, old value of f is printed and new value of f is calculated. 

0i: 1f: 
[i;17=~]
[i; $."! = " 1+$i: f;$.10, *f:]
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Fibonacci numbers:

Example for versions Morphett's FALSE

This example uses iterative method of calculating Fibonacci numbers. Variables a and b store current numbers, variable i is loop counter. 

0i: 1a: 1b:
[i;16=~]
[a; $. ", " $ b; $ a: + b: i;1+i:]
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"..."

CamelCase:

Example for versions Morphett's FALSE

The input string is processed character by character. In Morphett’s FALSE strings are entered in a pop-up window, and end of input is marked by an empty line, which is then converted to -1 value. That’s why -1 is used for breaking the loop. Variable s stores “whether the previous character was a space” sign. Conditional commands execution (?) allows to run only if-then conditions; to implement else branch, one has to copy the condition (stored in variable l — whether the current character is a letter), invert it and use another ?. 

1_s: ^
[$1_=~]
[ $$ 96> \123\> & [32-]?
  $$ 64> \91\> & $l: [s;~[32+]? , 0s:]? l;~[1_s: %]?
^]
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