Cyclone

Writing and Improvising a C-Clone interpreter

The language tokens being considered are:

TOKEN	EXAMPLE
LBRACE	' { '
RBRACE	' } '
LPAREN	' ( '
RPAREN	' ) '
ASSIGN	' = '
COMMA	' , '
DIGIT	123
FLOAT	3.14
ADDOP	' + ' , ' - '
MULOP	' * ' , ' / ', ' % '
LT	' < '
GT	' > '
EQ	' =='
LE	' <='
GE	' >= '
TYPE	' int '
IDENT	' i ' , ' tree '

The production rules to evaluating code:

Note, the terms in capitals imply the token should be consumed when parsing

name	definition
program	MAIN block
block	LBRACE statement_list RBRACE
statement_list	[statement *(SEMI statement) [SEMI]]
statement	(expr SEMI | declaration | block)
expr	addop *(ASSIGN expr)
addop	term *((PLUS/MINUS) expr)
mulop	atom ((MUL/DIV) expr)
atom	(PLUS/MINUS) atom | INTEGER | LPAREN expr RPAREN | IDENTIFIER
declaration	type IDENTIFIER [ASSIGN expr] SEMI
type	INT,FLOAT //TODO: IMPLEMENT FLOAT

Pay attention to the definition of statement list, here I'm saying that it is possible to have an empty statement list, as well as that the last statement doesn't necesarily need a closing SEMI. This is because I'm using rust syntax, in which if the last statement doesn't use a closing semi, it is considered a return value.

Proposed Grammar for future versions:

name	definition
function	TYPE IDENTIFIER argument_list block
argument_list	LPAREN argument *(COMMA argument) RPAREN
argument	TYPE IDENT