Topple/Topple 1

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Interpreter Sources

• Topple 1 (C99) (Unix only)
• Topple 1 (C++)

Overview

The first working version of Topple, completed on June 22nd, 2025.

Single-Character Commands

Unless otherwise specified, whitespace in any given code example is purely for organization

Command	Description	Example(s)	Output
.	"Admits” a given character as well as activates most other command characters Does not ignore whitespace	a. b. c.	None
@	Outputs all admitted characters and deletes them	a.b.c. @	abc
,	Outputs characters without admitting them Does not ignore whitespace	a,b,c,	abc
!	Takes user input	!. @	Whatever the user inputs
?	Compares the last two admitted values. Returns ‘1’ if the two are the same or ‘0’ if the two are not the same	a.b.?. @	0
#	Returns a random number between 0 and 9	#. @	0-9
&	Outputs all admitted characters without deleting them	a.b.c. &	abc
|	Deletes all admitted characters	a.b.c.| @	None
:	Outputs an admitted character at a given index Does not ignore whitespace	a.b.c. 0:	a
;	Takes admitted character from a given index and copies it. Does not ignore whitespace	a.b.c. 0; @	abca
=	Defines variables Does not ignore whitespace	a=1	None
~	Clears console	a.b.c. @ ~	None
*	Quits the program

In hindsight, creating a command that relies entirely on indexes in a language that only allow integers between 0 and 9 wasn't a good idea.

Multi-character Commands

None of these will ignore whitespace

Command	Description	Example(s)	Output
^.	"Admits" a given variable	a=1 a^. @	1
^+	Increments a given variable by 1	a=1 a^+ a^. @	2
^-	Decrements a given variable by 1	a=1 a^- a^. @	0
<...>	FOR Loop, loops as many times as the last admitted character	3.<a.@>	aaa
(...)	IF Statement, conditionally runs code if and only if the last admitted character was not equal to 0	1.(a.@)	a
[...]	ELSE Statement, will run only if the last IF Statement did not	0.(a.@)[b.@]	b
{...}	WHILE Loop, Takes a given variable and loops for as long as it is non-zero Variable does not need to be manually called	v=1 v.{a.@} v=1 v.{a.@ v=0}	aaaaaaaaaaa... a
_..._	Used for commenting	_a.b.c.@_	None

Special Characters

Character	Description
\	New Line (\n)

Example Code

Hello, world!

H,e,l,l,o,, ,w,o,r,l,d,!,

Hello, world! (but unnecessarily longer)

a=1

2.<
    a^.(
        H.e.l.    
    )[
        w.o.r.
    ]
    l.
    a^.(
        o.,. .|
    )[
        d.
    ]
    @
    a=0
>
!,

Computational Class

Topple 1 is Turing-complete, as it can easily be compiled from The Waterfall Model. First, create a variable for every waterclock. Then define a variable Q, thats equal to one. Then all the code after this point of translation is contained in a:

Q.{...}

Then, for every variable x, create an if statement:

x^.(| x^-)[| ...]

In the ... section, every variable must be incremented an equal amount to x's zeroing trigger.