Concept for a more readable functional programming language

gistfile1.txt

# declaring putc as an external function with implicit io
int putchar(io $, char c):
	implio cimport "putchar"

# print function
none print(io $, char ch):
	putchar($, ch); nothing

none print(io $, [char] []): nothing
none print(io $, [char] ch:str):
	print($, ch);
	print($, str)

none print(io $, integer 0): print($, '0')
none print(io $, integer i):
	if i < 0
		print($, '-');
		print($, -i)
	print($, i / 10);
	print($, char((i % 10) + '0'))

# factorial function
integer fact(integer 0): 1
integer fact(integer n): n * fact(n - 1)

# main function
none main(io $):
	print($, "The factorial of 10 is: ");
	print($, fact(10))

lang.txt

digit:
	0123456789

number:
	digit
	digit number
	number . number

idchar:
	abcdefghijklmnopqrstuvwxyz
	ABCDEFGHIJKLMNOPQRSTUVWXYZ
	$_

idcont:
	digit
	idchar
	digit idcont
	idchar idcont

symbol:
	idchar
	idchar idcont

string:
	char
	char string

escchar:
	abfnrtv\'"

char:
	digit
	idchar
	whitespace
	\ escchar

expression:
	let symdef expression
	if expression expression expression
	number
	" string "
	' char '
	symbol
	expression ( expression-list )

expression-list:
	expression
	expression , expression-list

vardecl:
	type symbol

funcdecl:
	type symbol ( param-list )

symdecl:
	vardecl
	funcdecl

vardef:
	vardecl = expression

funcdef:
	funcdecl : expression

symdef:
	vardef
	funcdef

param-list:
	symdecl
	symdecl , param-list

file:
	funcdef
	funcdef file