commit de0377397f6adecb9e3ebc20d0d0e3a8c458be1a
Author: Nikolaj Gade <nikolaj@ingemanngade.net>
Date:   Mon Feb 19 08:29:15 2024 +0100

    :tada:

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..c40d955
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,9 @@
+**/.vscode/
+**/__pycache__/
+**/*.aux
+**/*.fdb_latexmk
+**/*.fls
+**/*.log
+**/*.out
+**/*.synctex.gz
+**/*.xdv
\ No newline at end of file
diff --git a/documentation/plthy.pdf b/documentation/plthy.pdf
new file mode 100644
index 0000000..abb02c2
Binary files /dev/null and b/documentation/plthy.pdf differ
diff --git a/documentation/plthy.tex b/documentation/plthy.tex
new file mode 100644
index 0000000..05d9301
--- /dev/null
+++ b/documentation/plthy.tex
@@ -0,0 +1,35 @@
+\documentclass[a4paper]{paper}
+\usepackage[margin=2.5cm]{geometry}
+
+\begin{document}
+    \begin{center}
+    \begin{tabular}{|lcl|}
+        \hline
+        \textit{program} & $\rightarrow$ & \texttt{hello} \texttt{|} \textit{statements}  \texttt{goodbye} \texttt{|} \\ \hline \hline
+        \textit{statements} & $\rightarrow$ & \\ \hline
+        \textit{statements} & $\rightarrow$ & \textit{statement} \texttt{|} \textit{statements} \\ \hline\hline
+        \textit{statement} & $\rightarrow$ & \\ \hline
+        \textit{statement} & $\rightarrow$ & \texttt{maybe} \textit{statement}\\ \hline
+        \textit{statement} & $\rightarrow$ & \texttt{do} \textit{command}\\ \hline
+        \textit{statement} & $\rightarrow$ & \texttt{[} \textit{statements} \texttt{]}\\ \hline
+        \textit{statement} & $\rightarrow$ & \textit{statement} \texttt{if} \textit{expression} \\ \hline
+        \textit{statement} & $\rightarrow$ & \textit{statement} \texttt{because} \textit{expression} \\ \hline
+        \textit{statement} & $\rightarrow$ & \texttt{until} \textit{expression} \textit{statement} \\ \hline
+        \textit{statement} & $\rightarrow$ & \textit{expression} \texttt{->} \textbf{id} \\ \hline
+        \textit{statement} & $\rightarrow$ & \texttt{define} \textbf{function} \texttt{<} \textbf{numeral} \texttt{>} \texttt{as} \textit{statement} \\ \hline
+        \textit{statement} & $\rightarrow$ & \texttt{return} \textit{expression} \\ \hline\hline
+        \textit{command} & $\rightarrow$ & \textbf{builtin} \texttt{<} \textit{expressions} \texttt{>} \\ \hline
+        \textit{command} & $\rightarrow$ & \texttt{"} \textbf{function} \texttt{" <} \textit{expressions} \texttt{>} \\ \hline\hline
+        \textit{expressions} & $\rightarrow$ & \\ \hline
+        \textit{expressions} & $\rightarrow$ & \textit{expression} \texttt{;} \textit{expressions} \\ \hline\hline
+        \textit{expression} & $\rightarrow$ & \textbf{string} \\ \hline
+        \textit{expression} & $\rightarrow$ & \textbf{numeral} \\ \hline
+        \textit{expression} & $\rightarrow$ & \textbf{boolean} \\ \hline
+        \textit{expression} & $\rightarrow$ & \texttt{\{} \textit{expressions} \texttt{\}} \\ \hline
+        \textit{expression} & $\rightarrow$ & \texttt{(} \textit{expression} \texttt{)} \\ \hline
+        \textit{expression} & $\rightarrow$ & \textit{expression} \textbf{binop} \textit{expression} \\ \hline
+        \textit{expression} & $\rightarrow$ & \texttt{variable} \textbf{id}\\ \hline
+        \textit{expression} & $\rightarrow$ & \textit{statement} \\ \hline
+    \end{tabular}
+    \end{center}
+\end{document}
\ No newline at end of file
diff --git a/plthy b/plthy
new file mode 100755
index 0000000..d036cea
--- /dev/null
+++ b/plthy
@@ -0,0 +1,43 @@
+#! /home/nikolaj/.pyenv/shims/python
+"""
+Usage:
+    plthy (-h| --help)
+    plthy (-i| -c) FILE
+
+Options:
+    -h --help   Print this help screen
+    -i          Run the interpreter
+    -c          Run the compiler
+    FILE        The file to compile/interpret
+"""
+from docopt import docopt
+
+from plthy_impl.lexer import Lexer
+from plthy_impl.parser import Parser
+from plthy_impl.ast_nodes import Program
+
+def main():
+    args = docopt(__doc__)
+    file_path = args["FILE"]
+    with open(file_path, "r", encoding="utf-8") as file_pointer:
+        program_text = file_pointer.read() + "\n"
+
+    lexer = Lexer().get_lexer()
+    parser = Parser()
+
+    tokens = lexer.lex(program_text)
+    # for t in tokens:
+    #     print(t)
+
+    program = parser.parse(tokens)
+
+    if isinstance(program, Program):
+        if args["-i"]:
+            program.eval()
+        else:
+            raise Exception("Compiler not implemented")
+    else:
+        raise Exception("Output not of type 'Program'", type(program))
+
+if __name__ == "__main__":
+    main()
diff --git a/plthy_impl/ast_nodes.py b/plthy_impl/ast_nodes.py
new file mode 100644
index 0000000..acc2a45
--- /dev/null
+++ b/plthy_impl/ast_nodes.py
@@ -0,0 +1,224 @@
+import random
+
+from rply.token import BaseBox
+
+def rep_join(l):
+    format_string = ',\n'.join(
+        [repr(i) if not isinstance(i, str) else i for i in l]
+    ).replace('\n', '\n  ')
+
+    if format_string != "":
+        format_string = f"\n  {format_string}\n"
+
+    return format_string
+
+class Exp(BaseBox):
+    def eval(self, vtable, ftable):
+        return vtable, ftable, None
+
+class ExpNumeral(Exp):
+    def __init__(self, value: int):
+        self.value = value
+
+    def eval(self, vtable, ftable):
+        return vtable, ftable, self.value
+
+class ExpString(Exp):
+    def __init__(self, value: str):
+        self.value = value
+
+    def eval(self, vtable, ftable):
+        return vtable, ftable, self.value
+
+class ExpVariable(Exp):
+    def __init__(self, variable_id: str):
+        self.variable_name = variable_id
+
+    def eval(self, vtable, ftable):
+        return vtable, ftable, vtable[self.variable_name]
+
+class ExpABinop(Exp):
+    def __init__(self,op: str,exp1: Exp, exp2: Exp):
+        self.op = op
+        self.exp1 = exp1
+        self.exp2 = exp2
+
+    def eval(self, vtable, ftable):
+        if self.op == "+":
+            vtable, ftable, r1 = self.exp1.eval(vtable, ftable)
+            vtable, ftable, r2 = self.exp2.eval(vtable, ftable)
+            return vtable, ftable, r1+r2
+        elif self.op == "-":
+            vtable, ftable, r1 = self.exp1.eval(vtable, ftable)
+            vtable, ftable, r2 = self.exp2.eval(vtable, ftable)
+            return vtable, ftable, r1-r2
+        elif self.op == "*":
+            vtable, ftable, r1 = self.exp1.eval(vtable, ftable)
+            vtable, ftable, r2 = self.exp2.eval(vtable, ftable)
+            return vtable, ftable, r1*r2
+        elif self.op == "/":
+            vtable, ftable, r1 = self.exp1.eval(vtable, ftable)
+            vtable, ftable, r2 = self.exp2.eval(vtable, ftable)
+            return vtable, ftable, r1/r2
+        elif self.op == "=":
+            vtable, ftable, r1 = self.exp1.eval(vtable, ftable)
+            vtable, ftable, r2 = self.exp2.eval(vtable, ftable)
+            return vtable, ftable, r1 == r2
+        else:
+            raise Exception(f"Binop {self.op} not implemented")
+
+class ExpArg(Exp):
+    def __init__(self, arg: int):
+        self.arg = arg
+
+    def eval(self, vtable, ftable):
+        n = vtable["#ARGS"] - self.arg
+
+        return vtable, ftable, vtable[f"#{n}"]
+
+class Command(BaseBox):
+    def eval(self, vtable, ftable):
+        return vtable, ftable, None
+
+class Builtin(Command):
+    def __init__(self, builtin: str, args: list[Exp]):
+        self.builtin = builtin
+        self.args = args
+
+    def eval(self, vtable, ftable):
+        if self.builtin == "print":
+            prints = []
+            for arg in self.args:
+                vtable, ftable, result = arg.eval(vtable, ftable)
+                prints.append(str(result))
+
+            print("   ".join(prints))
+
+            return vtable, ftable, None
+        else:
+            raise Exception(f"Unknown builtin {self.builtin}")
+
+class Do(BaseBox):
+    def __init__(self, command: Command):
+        self.command = command
+
+    def eval(self, vtable, ftable):
+        return self.command.eval(vtable, ftable)
+
+class Statement(BaseBox):
+    def eval(self, vtable, ftable):
+        return vtable, ftable, None
+
+class StatementSet(Statement):
+    def __init__(self, expression: Exp, variable: str):
+        self.expression = expression
+        self.variable_name = variable
+
+    def eval(self, vtable, ftable):
+        vtable, ftable, result = self.expression.eval(
+            vtable, ftable
+        )
+        vtable[self.variable_name] = result
+        return vtable, ftable, None
+
+class StatementDefine(Statement):
+    def __init__(self, function_name : str, parameters: int, statement: Statement):
+        self.function_name = function_name
+        self.statement = statement
+        self.parameters = parameters
+
+    def eval(self, vtable, ftable):
+        ftable[self.function_name] = (self.parameters, self.statement)
+        return vtable, ftable, None
+
+class StatementReturn(Statement):
+    def __init__(self, expression: Exp):
+        self.value = expression
+
+    def eval(self, vtable, ftable):
+        vtable, ftable, result = self.value.eval(vtable, ftable)
+        vtable["#return"] = result
+        return vtable, ftable, result
+
+class Scope(Statement):
+    def __init__(self, statements: list[Statement]):
+        self.statements = statements
+
+    def eval(self, vtable, ftable):
+        result = None
+        for statement in self.statements:
+            vtable, ftable, _ = statement.eval(vtable, ftable)
+            if "#return" in vtable:
+                result = vtable["#return"]
+                del vtable["#return"]
+                break
+
+        return vtable, ftable, result
+
+class Call(Statement):
+    def __init__(self, function_name: str, arguments: list[Exp]):
+        self.function_name = function_name
+        self.arguments = arguments
+
+    def eval(self, vtable, ftable):
+        assert len(self.arguments) == ftable[self.function_name][0]
+
+        args = []
+        for argument in self.arguments:
+            vtable, ftable, result = argument.eval(vtable,ftable)
+            args.append(result)
+
+        n = vtable["#ARGS"]-1
+
+        for i, arg in enumerate(args):
+            vtable[f"#{n+len(args)-i}"] = arg
+
+        vtable["#ARGS"] += len(args)
+
+        vtable, ftable, result = ftable[self.function_name][1].eval(vtable, ftable)
+
+        if "#return" in vtable:
+            del vtable["#return"]
+
+        vtable["#ARGS"] -= len(args)
+
+        return vtable, ftable, result
+
+class StatementIf(Statement):
+    def __init__(self, statement: Statement, condition):
+        self.statement = statement
+        self.condition = condition
+
+    def eval(self, vtable, ftable):
+        vtable, ftable, result = self.condition.eval(vtable, ftable)
+        if result:
+            return self.statement.eval(vtable, ftable)
+        else:
+            return vtable, ftable, None
+
+class Maybe(BaseBox):
+    def __init__(self, statement : Statement):
+        self.statement = statement
+
+    def eval(self, vtable, ftable):
+        if random.randint(0,1) == 1:
+            return self.statement.eval(vtable,ftable)
+        else:
+            return vtable, ftable, None
+
+class Program(BaseBox):
+    def __init__(self, statements: list[Statement]) -> None:
+        self.statements = statements
+
+    def __repr__(self) -> str:
+        statements_string = f"statements([{rep_join(self.statements)}])"
+        return statements_string
+
+    def eval(self, *_):
+        vtable = {"#ARGS": 0}
+        ftable = {}
+
+        for statement in self.statements:
+            vtable, ftable, _ = statement.eval(vtable, ftable)
+            if "#return" in vtable:
+                break
diff --git a/plthy_impl/lexer.py b/plthy_impl/lexer.py
new file mode 100644
index 0000000..e68666e
--- /dev/null
+++ b/plthy_impl/lexer.py
@@ -0,0 +1,74 @@
+from string import ascii_letters, digits
+from rply import LexerGenerator
+
+VALID_CHARACTERS = ascii_letters+"_"+digits
+
+KEYWORD_TOKENS = [("KEYWORD_"+i.upper(), i) for i in [
+    "hello",
+    "goodbye",
+    "maybe",
+    "do",
+    "if",
+    "because",
+    "until",
+    "define",
+    "as",
+    "variable",
+    "return",
+    "argument"
+]]
+
+BUILTIN_TOKENS = [("BUILTIN", i) for i in [
+    "print"
+]]
+
+DATA_TOKENS = [
+    ("DATA_STRING", r"\'.*?\'"),
+    ("DATA_NUMERAL", r"\d+(\.\d+)?")
+]
+
+SYMBOL_TOKENS = [
+    ("SYMBOL_SET", r"\-\>"),
+    ("SYMBOL_LPARENS", r"\("),
+    ("SYMBOL_RPARENS", r"\)"),
+    ("SYMBOL_LBRACKET", r"\["),
+    ("SYMBOL_RBRACKET", r"\]"),
+    ("SYMBOL_LCURL", r"\{"),
+    ("SYMBOL_RCURL", r"\}"),
+    ("SYMBOL_PLUS", r"\+"),
+    ("SYMBOL_MINUS", r"\-"),
+    ("SYMBOL_TIMES", r"\*"),
+    ("SYMBOL_DIVIDE", r"\/"),
+    ("SYMBOL_COMMA", r"\,"),
+    ("SYMBOL_COLON", r"\:"),
+    ("SYMBOL_SEMICOLON", r"\;"),
+    ("SYMBOL_PIPE", r"\|"),
+    ("SYMBOL_QUOTE", r"\""),
+    ("SYMBOL_LT", r"\<"),
+    ("SYMBOL_GT", r"\>"),
+    ("SYMBOL_EQUALS", r"\="),
+    ("SYMBOL_DOLLAR", r"\$")
+]
+
+ALL_TOKENS = (
+    KEYWORD_TOKENS +
+    BUILTIN_TOKENS +
+    DATA_TOKENS +
+    SYMBOL_TOKENS +
+    [("ARG", r"\#\d+")] +
+    [("ID", f"[{VALID_CHARACTERS}]+")]
+)
+
+
+class Lexer():
+    def __init__(self):
+        self.lexer = LexerGenerator()
+
+    def _add_tokens(self):
+        for token in ALL_TOKENS:
+            self.lexer.add(*token)
+        self.lexer.ignore(r"[\s\n]+|//.*\n")
+
+    def get_lexer(self):
+        self._add_tokens()
+        return self.lexer.build()
diff --git a/plthy_impl/parser.py b/plthy_impl/parser.py
new file mode 100644
index 0000000..908c6db
--- /dev/null
+++ b/plthy_impl/parser.py
@@ -0,0 +1,118 @@
+from rply import ParserGenerator
+
+from plthy_impl.lexer import ALL_TOKENS
+from plthy_impl import ast_nodes
+
+class Parser():
+    def __init__(self):
+        self.pg = ParserGenerator(
+            [i[0] for i in ALL_TOKENS],
+            precedence=[
+                ('left', ["KEYWORD_MAYBE", "KEYWORD_RETURN"]),
+                ('left', ["KEYWORD_IF", "KEYWORD_DEFINE", "KEYWORD_AS"]),
+                ('left', ["KEYWORD_DO", "BUILTIN"]),
+                ('left', ["SYMBOL_EQUALS", "SYMBOL_SET"]),
+                ('left', ["SYMBOL_PLUS", "SYMBOL_MINUS"]),
+                ('left', ["SYMBOL_TIMES", "SYMBOL_DIVIDE"])
+            ]
+        )
+
+    def parse(self, token_input) -> ast_nodes.BaseBox:
+        # Top-level program stuff
+        @self.pg.production('program : KEYWORD_HELLO SYMBOL_PIPE statements KEYWORD_GOODBYE SYMBOL_PIPE')
+        def program(tokens):
+            return ast_nodes.Program(tokens[2])
+
+        ## statements ##
+        @self.pg.production('statements : ')
+        def statements_none(_):
+            return []
+
+        @self.pg.production('statements : statement SYMBOL_PIPE statements')
+        def statements(tokens):
+            return [tokens[0]] + tokens[2]
+
+        ## statement ##
+        @self.pg.production('statement : SYMBOL_DOLLAR expression SYMBOL_SET ID', precedence="SYMBOL_SET")
+        def statement_set(tokens):
+            return ast_nodes.StatementSet(tokens[1], tokens[3].value)
+
+        @self.pg.production('statement : KEYWORD_DO command')
+        def statement_do(tokens):
+            return ast_nodes.Do(tokens[1])
+
+        @self.pg.production('statement : KEYWORD_MAYBE statement')
+        def statement_maybe(tokens):
+            return ast_nodes.Maybe(tokens[1])
+
+        @self.pg.production('statement : statement KEYWORD_IF expression')
+        def statement_if(tokens):
+            return ast_nodes.StatementIf(tokens[0], tokens[2])
+
+        @self.pg.production('statement : KEYWORD_DEFINE ID SYMBOL_LT DATA_NUMERAL SYMBOL_GT KEYWORD_AS statement', precedence="KEYWORD_DEFINE")
+        def statement_define(tokens):
+            return ast_nodes.StatementDefine(tokens[1].value, int(tokens[3].value), tokens[6])
+
+        @self.pg.production('statement : KEYWORD_RETURN expression')
+        def statement_return(tokens):
+            return ast_nodes.StatementReturn(tokens[1])
+
+        @self.pg.production('statement : SYMBOL_LBRACKET statements SYMBOL_RBRACKET')
+        def statement_scope(tokens):
+            return ast_nodes.Scope(tokens[1])
+
+        ## command ##
+        @self.pg.production('command : BUILTIN SYMBOL_LT expressions SYMBOL_GT')
+        def command_builtin(tokens):
+            return ast_nodes.Builtin(tokens[0].value, tokens[2])
+
+        @self.pg.production('command : SYMBOL_QUOTE ID SYMBOL_QUOTE SYMBOL_LT expressions SYMBOL_GT')
+        def command_call(tokens):
+            return ast_nodes.Call(tokens[1].value,tokens[4])
+
+        ## expressions ##
+        @self.pg.production('expressions : ')
+        def expressions_none(_):
+            return []
+
+        @self.pg.production('expressions : expression SYMBOL_SEMICOLON expressions ')
+        def expressions(tokens):
+            return [tokens[0]] + tokens[2]
+
+        ## expression ##
+        @self.pg.production('expression : DATA_NUMERAL')
+        def exp_numeral(tokens):
+            return ast_nodes.ExpNumeral(float(tokens[0].value))
+
+        @self.pg.production('expression : DATA_STRING')
+        def exp_string(tokens):
+            return ast_nodes.ExpString(tokens[0].value[1:-1])
+
+        @self.pg.production('expression : statement', precedence="KEYWORD_IF")
+        def exp_statement(tokens):
+            return(tokens[0])
+
+        @self.pg.production('expression : KEYWORD_VARIABLE ID')
+        def exp_variable(tokens):
+            return ast_nodes.ExpVariable(tokens[1].value)
+
+        @self.pg.production('expression : expression SYMBOL_PLUS expression')
+        @self.pg.production('expression : expression SYMBOL_MINUS expression')
+        @self.pg.production('expression : expression SYMBOL_TIMES expression')
+        @self.pg.production('expression : expression SYMBOL_DIVIDE expression')
+        @self.pg.production('expression : expression SYMBOL_EQUALS expression')
+        def exp_a_binop(tokens):
+            return ast_nodes.ExpABinop(tokens[1].value,tokens[0],tokens[2])
+
+        @self.pg.production('expression : KEYWORD_ARGUMENT ARG')
+        def exp_arg(tokens):
+            return ast_nodes.ExpArg(int(tokens[1].value[1:]))
+
+        ## Error Handling ##
+        @self.pg.error
+        def error_handle(token):
+            raise Exception(token.name, token.value, token.source_pos)
+
+        ## Finish ##
+        parser = self.pg.build()
+        return parser.parse(token_input)
diff --git a/tests/fib.plthy b/tests/fib.plthy
new file mode 100644
index 0000000..3fd522a
--- /dev/null
+++ b/tests/fib.plthy
@@ -0,0 +1,12 @@
+hello|
+define fib<1> as [
+    return 1 if argument #1 = 1|
+    return 1 if argument #1 = 2|
+    return do "fib"<argument #1-1;> + do "fib"<argument #1-2;>|
+]|
+do print<do "fib"<1;>;>|
+do print<do "fib"<2;>;>|
+do print<do "fib"<3;>;>|
+do print<do "fib"<6;>;>|
+do print<do "fib"<10;>;>|
+goodbye|
\ No newline at end of file
diff --git a/tests/function.plthy b/tests/function.plthy
new file mode 100644
index 0000000..405d73e
--- /dev/null
+++ b/tests/function.plthy
@@ -0,0 +1,4 @@
+hello|
+define five<0> as return 5|
+do print<do "five"<>;>|
+goodbye|
\ No newline at end of file
diff --git a/tests/if.plthy b/tests/if.plthy
new file mode 100644
index 0000000..b826fe4
--- /dev/null
+++ b/tests/if.plthy
@@ -0,0 +1,5 @@
+hello|
+$2 -> x|
+do print<'a';> if variable x = 1|
+do print<'b';> if variable x = 2|
+goodbye|
\ No newline at end of file
diff --git a/tests/math.plthy b/tests/math.plthy
new file mode 100644
index 0000000..2e1cd5a
--- /dev/null
+++ b/tests/math.plthy
@@ -0,0 +1,10 @@
+hello|
+$1 -> x|
+$2 -> y|
+$5 -> z|
+$variable x+variable y -> z| // 3
+$5-variable z -> z| // 2
+$2*variable z -> x| // 4
+$variable x/variable y -> y| // 2
+do print<variable x;variable y;variable z;>|
+goodbye|
\ No newline at end of file
diff --git a/tests/maybe.plthy b/tests/maybe.plthy
new file mode 100644
index 0000000..ab547bd
--- /dev/null
+++ b/tests/maybe.plthy
@@ -0,0 +1,5 @@
+hello|
+$1 -> x|
+maybe $variable x + 1 -> x|
+do print<variable x;>|
+goodbye|
\ No newline at end of file
diff --git a/tests/none.plthy b/tests/none.plthy
new file mode 100644
index 0000000..f749478
--- /dev/null
+++ b/tests/none.plthy
@@ -0,0 +1,2 @@
+hello|
+goodbye|
\ No newline at end of file
diff --git a/tests/precedence.plthy b/tests/precedence.plthy
new file mode 100644
index 0000000..34c6ade
--- /dev/null
+++ b/tests/precedence.plthy
@@ -0,0 +1,6 @@
+hello|
+$ 1 + 2 * 3 -> x|
+do print<variable x;>|
+$ 5 -> y if variable x = 7|
+do print<variable y;>|
+goodbye|
\ No newline at end of file
diff --git a/tests/scope.plthy b/tests/scope.plthy
new file mode 100644
index 0000000..a17f1a2
--- /dev/null
+++ b/tests/scope.plthy
@@ -0,0 +1,6 @@
+hello|
+[
+    $5 -> x|
+    do print<variable x;>|
+]|
+goodbye|
\ No newline at end of file
diff --git a/tests/variable.plthy b/tests/variable.plthy
new file mode 100644
index 0000000..b4e1676
--- /dev/null
+++ b/tests/variable.plthy
@@ -0,0 +1,4 @@
+hello|
+$2 -> x|
+do print<variable x;>|
+goodbye|
\ No newline at end of file