Copyright (C) 2001 Michael Leonhard
Mike Leonhard
mike at tamale dot net
http://tamale.net/

Vitamin C

Vitamin C is a simplistic programming language.  Three data types are supported,
integer, floating point, and string.

`sub' defines a subroutine.  Input data types are specified.
Output data types are inferred from the `return' statements.

Subroutines may take one parameter or none.  Subroutines may return one value 
or none.

// single line comment
/* nested /* comments */
*/
sub foo int a:
	return a
	;

sub main:
	int x = 1
	int b
	b := foo x
	return
	;


Tokenizer grammar:

identifier: alpha alphanum*
subkeyword: `s' `u' `b'
returnkeyword: `r' `e' `t' `u' `r' `n'
intkeyword: `i' `n' `t'
floatkeyword: `f' `l' `o' `a' `t'
stringkeyword: `s' `t' `r' `i' `n' `g'
integer: decimal | hexadecimal
decimal: decdigit decdigit*
hexadecimal: `0' `x' hexdigit hexdigit*
floatingpoint: frontfloat | bothfloat | backfloat
frontfloat: decdigit decdigit* `.'
bothfloat: decdigit decdigit* `.' decdigit decdigit*
backfloat: `.' decdigit decdigit*
string: `"' nonquote* `"'
nonquote: ` ' | `!' | escapedquote | #..[ | escapedbackslash | ]..~
escapedquote: `\' `"'
escapedbackslash: `\' `\'
alpha: a..z | A..Z
alphanum: a..z | A..Z | decdigit
decdigit: 1..0
hexdigit: decdigit | a..f | A..F
colonsymbol: `:'
assignsymbol: ':='
semicolonsymbol: `;'
leftparensymbol: `('
rightparensymbol: `)'
orsymbol: `|'
xorsymbol: `^'
lshsymbol: `<<'
rshsymbol: `>>'
gtsymbol: `>'
ltsymbol: `<'
equalsymbol: `='
subtractsymbol: `-'
addsymbol: `+'
multiplysymbol: `*'
dividesymbol: `/'
whitespace: ' ' | '\t' | '\r'
endline: '\n' | '\n' '\n'*


Parser grammar:

vitaminc: sub sub*
sub: subkeyword identifier block | subkeyword identifier definition block
block: colonsymbol statement* return semicolonsymbol
return: returnkeyword expression | returnkeyword
statement: definition | assignment | subcall
definition: intdefition | floatdefinition | stringdefinition
intdefinition: intkeyword identifier assignsymbol expression | intkeyword identifier
floatdefinition: floatkeyword identifier assignsymbol expression | floatkeyword identifier
stringdefinition: stringkeyword identifier assignsymbol expression | stringkeyword identifier
assign: identifer assignsymbol expression
subcall: identifier expression | identifier
expression: parens | integer | floatingpoint | string | subcall | or | xor | lsh | rsh | gt | lt | equal | subtract | add | multiply | divide
parens: leftparensymbol expression rightparensymbol
or: expression orsymbol expression
xor: expression xorsymbol expression
lsh: expression lshsymbol expression
rsh: expression rshsymbol expression
gt: expression gtsymbol expression
lt: expression ltsymbol expression
equal: expression equalsymbol expression
subtract: expression subtractsymbol expression
add: expression addsymbol expression
multiply: expression multiplysymbol expression
divide: expression dividesymbol expression

Operator precedence is as follows, from lowest to highest:
| ^ = << >> > < - + * /