TinyBASIC

BASIC is a custom programming language compiled with our custom compiler, Caveman. We use GNU Bison to process our custom CFGs and Lex to parse tokens. You can find examples of using our language in the examples directory.

Language & Compiler Specification

• Programming Language Name: BASIC
• Extension: .simp
• Compiler Name: Caveman

Language Features and Code Examples

Language Feature	Code Example
Integer scalar variable	var : int; var, otherVar : int;
One Dimensional Arrays of Integers	a = array[1000] type int;
Assignment statements	var ?= 10;
Arithmetic operators	+,-,*,/
Comparison operators	<,<=,==,>,>=,!=
While Loops	while (i < n) beginwhile doSomething endloop;
If-then-else statements	if (i < n) then doSomething endif else then doSomethingElse endelse
Read and Write statements	input n;, print n;
Comments	$comment
Functions with multiple parameters and return exactly one single scalar result	function sumOfTwoNumbersPlusFive; beginparams endparams beginlocals a = int; b = int; endlocals beginfuncbody input a; input b; return a + b + 5; endbody

Language Symbols and Token Names

Symbol in Language	Token Name
;	SEMICOLON
:	COLON
int	INT
==	EQUALS
array	ARRAY
function	FUNCTION
return	RETURN
?=	ASSIGN
type	TYPE
+	ADD
-	SUBTRACT
*	MULT
/	DIV
true	TRUE
false	FALSE
<	LESS_THAN
<=	LESS_THAN_EQ
>	GREAT_THAN
>=	GREAT_THAN_EQ
!=	NOT_EQ
$	(No token, this is a comment)
(	LEFT_PAREN
)	RIGHT_PAREN
[	LEFT_SQUARE_BRACKET
]	RIGHT_SQUARE_BRACKET
newline	NEWLINE
input	READ
print	WRITE
beginwhile	BEGIN_LOOP
endwhile	END_LOOP
beginparams	BEGIN_PARAMS
endparams	END_PARAMS
beginfuncbody	BEGIN_FUNC_BODY
endfuncbody	END_FUNC_BODY
beginlocals	BEGIN_LOCAL_VAR
endlocals	END_LOCAL_VAR
(Identifier like a, b, etc.)	IDENT XXXXX
Number (like 1, 2, 3)	NUM X
if	IF
else	ELSE
then	THEN
endif	END_IF
while	WHILE
ff	BREAK

Comments

• Comments start after $ and end after a newline. Comments can begin on any line, and only the characters after the $ will be ignored.

Valid Identifiers

• Identifiers must begin with an alphabet character. The identifier can include a number and/or lowercase/uppercase letters. However, identifiers cannoot contain special characters. For instance, abc : int and h3lLo : int would be accepted, but the following would not:
  @bc : int
h@llo : int.

Case Sensitivity

• Our language is case sensitive. Identifiers will not match with identifiers that have the same letters, but different case. For example:
  hello : int
Hello = 1
  

The above would throw an error because the h is different.

Additionally, keywords are case sensitive. Declaring an integer can only be done by using int, and not Int.

Whitespace

• Our language ignores whitespace in most cases. For example, the following block of code would be valid:

function doSomething; beginparams endparams beginlocals endlocals beginfuncbody return 3; endbody

Would be valid, and doSomething would still return 3.

One case where whitespace is ignored is comments (as specified earlier). Everything that comes after a $ will be ignored.