syntax.txt

Terminals:

    natural_number (regex: 0|[1-9][0-9]*)
    character (examples: 'a', '\'', '"', '\n')
    string (examples: "", "hello", "\treturn \"\";\n")
    ident (regex: [a-z][a-z0-9_']*|[A-Z][A-Z0-9_']*)

    Where, Let, Define, ... (a fixed finite subset of regex: [A-Z][a-z]+)

Nonterminals:

    Note: Each source file matches the "package" nonterminal.

package = expr { Where { binder } } .
binder = Let ( ident | tuple_pattern | function_pattern ) body
    | Define function_pattern body
    | Do body .
tuple_pattern = '{' { '_' | ident | tuple_pattern } '}' .
function_pattern = '[' ident param_pattern { param_pattern } ']' .
param_pattern = '_' | ident | tuple_pattern .
variant_pattern = '`' ident [ '.' ( '_' | ident | tuple_pattern ) ] .
body = { { binder } In } expr .
expr = natural_number | character | string |
    ident { '.' ( natural_number | ident ) } |
    '`' ident [ '.' expr ] |
    True |
    False |
    Prim ident |
    Package string |
    Func param_pattern { param_pattern } '.' body |
    For expr binder |
    Block body |
    unary_op expr |
    '(' expr { binary_op expr } ')' |
    '{' ( List { expr } | Record { ident [ ':' expr ] } | { expr } ) '}' |
    '[' expr expr { expr } ']' |
    If expr expr expr |
    And expr expr |
    Or expr expr |
    Cond { '|' expr body } ';' |
    Switch expr { '|' ( '_' | ident | [ '-' ] ( natural_number | character ) ) body } ';' |
    Match expr { '|' variant_pattern body } ';' |
    Continue '[' ident expr { expr } ']' |
    When expr { expr } End |
    Begin { expr } End expr .
unary_op = '-' | '!' .
binary_op = '+' | '-' | '*' | '=' | '<' [ '=' ] | '>' [ '=' ] | '!' '=' | ':' ':' .