Variables

Variable Naming Conventions

Variables in pometo follow the Erlang convention - they all start with an uppercase letter and may contain upper and lower case letters, the digits 0 to 9 and _ and @.

Like Erlang variables they are immutable - once you have bound a variable you cannot change its value.

Variables are bound with the let operator ←. (Note in this example we are prefixing the variable with _ the I am not being used prefix for operators. You don’t need this in the interpreter but if you write Pometo modules they won’t compile - you will get an error.

_MyVar99 ← 1 2 3

1 2 3

Variables can be used in place of values in other Pometo functions:

A ← 1 2 3
B ← 4 5 6
A + B

5 7 9

And of course they can be mixed and matched:

A ← 1 2 3
B ← 5 6 7
A + 4 5 6
1 2 3 - B

¯4 ¯4 ¯4

A ← 1 2 3
B ← 5 6 7
C ← A
D ← B
C ÷ D

0.2 0.3333333333333333 0.42857142857142855

If you try and use an unset variable you will get an error in your code

MyVar ← 1 2 3
55 66 77 + MYVar

Error
55 66 77 + MYVar
-----------^
VARIABLE NOT DEFINED [MYVar: variable is not defined ] on line 2 at character 12