A compiler for a custom language
- Install python3, llc and gcc
- Install rply:
pip3 install rply - Run main.py
UPPERCASE WORDS are terminals
"+" etc are also some simple terminals, usually operators.
lower-case-words are non-terminals.
This grammar uses the EBNF notation:
| -- means alternative.
( ) -- means grouping.
? after an item means it is optional.
+ after an item means "one or more of".
* means "zero or more of".
| Terminal | Token |
|---|---|
| ARRAY | "array" |
| ID | identifier |
| DOTDOT | ".." |
| LBRAK | "[" |
| RBRAK | "]" |
| SEMI | ";" |
| TUPLE | "tuple" |
| LOCAL | "local" |
| GLOBAL | "global" |
| DEFUN | "defun" |
| LPAR | "(" |
| RPAR | ")" |
| COMMA | "," |
| END | "end" |
| WHILE | "while" |
| DO | "do" |
| IF | "if" |
| THEN | "then" |
| ELSIF | "elsif" |
| ELSE | "else" |
| FOREACH | "foreach" |
| FOR | "for" |
| IN | "in" |
| DOT | "." |
| INT | integer literal |
| RETURN | "return" |
| "print" |
start symbol: input
input = ( statement | decl | defn )*
decl = ARRAY ID LBRAK expr DOTDOT expr RBRAK ( ID "=" expr )? SEMI
| LOCAL ID ("=" expr)? SEMI
| GLOBAL ID ("=" expr)? SEMI
def = DEFUN ID LPAR ID ( COMMA ID )* RPAR body END DEFUN
body = ( statement | decl )*
statement = lhs "=" expr SEMI
| lhs "<->" lhs SEMI
| WHILE bool-expr DO statement* END WHILE
| IF bool-expr THEN statement*
(ELSIF bool-expr THEN statement*)*
(ELSE statement*)? END IF
| FOREACH ID IN (range | array-id) DO statement* END FOR
| RETURN expr SEMI
| PRINT expr SEMI
array-id = ID
range = expr DOTDOT expr
bool-expr = expr bool-op expr
bool-op = "<" | ">" | "==" | "!=" | "<=" | ">="
lhs = lhs-item ( COMMA lhs-item )*
lhs-item =
| ID
| ID DOT INT
| ID LBRAK expr RBRAK
expr =
| expr COMMA expr
| expr ( "+" | "-" ) expr
| expr ( "*" | "/" ) expr
| LPAR expr RPAR
| ID
| ID expr
| ID DOT INT
| ID LBRAK expr RBRAK
| INT