Write Sy

Overview

Syntax

There are only two commands in syscript: the sy operator and the leaf operator.

The sy operator requires four position arguments. The sy operator subtracts the second argument from the first, stores the difference in a variable (the third argument), and branches to a different location in the code (the fourth arguments) if the sum is less than or equal to 0. One, both, or none of the third and fourth arguments can be an underscore, meaning ignore this argument.

The leaf defines the starting point of a branch that can be reached from the sy command.

Because this language is terrible, comments are contained within chevrons -- <<Some comment...>>. Also lines have to end in a semicolon (;) (not comment lines though).

All words / symbols

Word/Symbol	Usage	Meaning/Use
sy	sy op1 op2 op3 op4;	Subtract op2 from op1, store difference in op3, jump to op4
leaf	leaf op1;	Define starting point of a branch location named op1
_	sy op1 op2 _ op4;	Can be used in place of arg 3 or 4 -- means "nothing"
stdin	sy stdin op2 op3 op4;	Gets a number from the stdin
stdout	sy op1 op2 stout op4;	Prints ascii encoded symbol to stdout

Write

Open a file, write some commands, and then run it using syscript.py.

The following script prints "Hello, World!\n" three times. It does so using the following steps:

1. Set variable counter to 3
2. Print "Hello, World!\n"
   • This is done by not subtracting anything, and saving it to stdout
3. Subtract 1 from counter, branching to End if less than or equal to 0
4. If not, return to PrintHelloWorld (step 2)

leaf ControlVariables;
sy 3 0 counter _;

<<Test comment>>

leaf PrintHelloWorld;
sy 72 0 stdout _;
sy 101 0 stdout _;
sy 108 0 stdout _;
sy 108 0 stdout _;
sy 111 0 stdout _;
sy 44 0 stdout _;
sy 32 0 stdout _;
sy 119 0 stdout _;
sy 111 0 stdout _;
sy 114 0 stdout _;
sy 108 0 stdout _;
sy 100 0 stdout _;
sy 33 0 stdout _;
sy 10 0 stdout _;

leaf CounterChange;
sy counter 1 counter End;
sy 0 0 _ PrintHelloWorld;

leaf End;