grammar

program => (statement)*

statement => if | while | codeBlock | function | return | valueDeclaration | input | output | assignment | expression | typeDeclaration

if => "if" expression "then" (statement)* ("else" (statement)*)? "end"
while => "while" expression codeBlock
codeBlock => "do" program "end"
function => STRING "(" (STRING (",")*)* ")" functionReturnType codeBlock

functionReturnType => NOTHING | ":" typeNotation
return => "return" expression
valueDeclaration => "val" pattern (":" typeNotation)? "":=" expression
assignment => STRING ":=" expression
input => "input" STRING
output => "output" expression

typeNotation => primitiveType
primitiveType => "unit" | "list" | ((atomicType | functionType | tupleType) "list"?)
functionType => ("(" (typeNotation)? (","typeNotation)* ")" ("->" typeNotation)?)
tupleType => "(" typeNotation ("," typeNotation)* ")"
atomicType => STRING | CONSTRUCTOR

pattern => STRING (":" typeNotation)? | constructorPattern | tuplePattern
constructorPattern => CONSTRUCTOR tuplePattern
tuplePattern => "(" (pattern ","?)+ ")"



listDeclaration = "[" expressionList "]"
expressionList =  (expression (",")*)*

expression => logical
logical => equality ( ( "and" | "or" ) equality )*
equality => comparison ( ( "!=" | "==" ) comparison )*
comparison => addition ( ( ">" | ">=" | "<" | "<=" ) addition )*
addition => multiplication ( ( "-" | "+" ) multiplication )*
multiplication => unary ( ( "/" | "*" ) unary )*
unary => ( "!" | "-" ) unary | primary ("[" expressionList "]" | "(" expressionList ")")*
primary => NUMBER | STRING | "false" | "true" | "(" expression ")" | listDeclaration
anonymousFunction => "function" "(" (STRING typeNotation(",")?)*  ")" functionReturnType codeBlock


typeDeclaration => "type" STRING ("<" ((STRING)(",")?)+ ">")? ":=" typeDefinition
typeDefinition => STRING ("of" typeNotation)?