FibLang
A Programming Language just for writing Fibonacci number program. :)
def fib(x)
x < 2 ? 1 : fib(x - 2) + fib(x - 1)
for n from 1 to 30
puts(fib(n))
Build and Run demo
> make
...
./fib fib.fib
1
2
3
5
8
13
21
34
55
89
144
233
...PEG grammar
# Syntax
START ← STATEMENTS
STATEMENTS ← (DEFINITION / EXPRESSION)*
DEFINITION ← 'def' Identifier '(' Identifier ')' EXPRESSION
EXPRESSION ← TERNARY
TERNARY ← CONDITION ('?' EXPRESSION ':' EXPRESSION)?
CONDITION ← INFIX (ConditionOperator INFIX)?
INFIX ← CALL (InfixOperator CALL)*
CALL ← PRIMARY ('(' EXPRESSION ')')?
PRIMARY ← FOR / Identifier / '(' EXPRESSION ')' / Number
FOR ← 'for' Identifier 'from' Number 'to' Number EXPRESSION
# Token
ConditionOperator ← '<'
InfixOperator ← '+' / '-'
Identifier ← !Keyword < [a-zA-Z][a-zA-Z0-9_]* >
Number ← < [0-9]+ >
Keyword ← 'def' / 'for' / 'from' / 'to'
%whitespace ← [ \t\r\n]*
%word ← [a-zA-Z]