# SI413 Fall 2026 Unit 1 Labs

language_name: Painting Programming Language (PPL)

notes_from_prof: |
    Language designed by Daniel Stein and reviewed by Jake Lawrence.
    PPL stands for Painting Programming Language.
    Rather than using any special operators, the operators look
    like a backslash followed by some operator name.
    This makes the code a little more verbose but maybe more readable?
    And of course it's all about painting.


example_program: |
    idea Ask for name
    paint /color{What is your name?}

    idea Print name from console
    paint /color{Hello}/mix/dipBrush

    idea Ask for a noun and adjective
    paint /color{Enter a noun and an adjective::}

    idea Get both inputs, reverse the first one, and concatenate
    paint /dipBrush/complement/mix/color{ is not }/mix/dipBrush


# Task 3

language_syntax: |
    There are 4 kinds of Expressions

        A series of characters that start with '/color{' and end with '}'.
        There are two escape sequences, ':}', and '::'.

        The command '/dipBrush'

        Two expressions separated by '/mix'

        An expression followed by '/complement'

    A comment is a line in the program that starts with 'idea'

    A Statement is a new line that starts 'paint '

    A Program is a sequence of Statements with only one on each line



language_semantics: |
    The command /dipBrush reads an entire line from the terminal,
    removing the new line character

    Evaluating two Expression delimited by '/mix' concatenates the string literals

    Evaluating /complement reverses the Expression before it.

    /complement has higher precedence than /mix.

    The escape sequences, ':}' and '::', evaluate to '}' and ':' respectively

    A Statement that starts with 'paint ' evaluates the expressions left
    to right and prints the result on its own line.

    A Program executes each Statement in order.