This was my attempt at implementing a very basic compiler that takes Tiny BASIC as input and generates C code.
The following grammar is the grammar that was implemented.
program = { statement }
statement = "PRINT" ( expression | string ) nl |
"IF" comparison "THEN" nl { statement } "ENDIF" nl |
"WHILE" comparison "REPEAT" nl { statement } "ENDWHILE" |
"LABEL" ident nl | "GOTO" ident nl | "LET" ident "=" expression nl |
"INPUT" ident nl
comparison = expression(( "==" | "!=" | ">" | ">=" | "<" | "<=" ) expression )+
expression = term {( "-" | "+") term }
term = unary {( "/" | "+" ) term }
unary = [ "+" | "-" ] primary
primary = number | ident
nl = '\n'+
Structure of the compiler is fairly straight forward.
The Lexer class is in charge of generating tokens from the input. Tokens are essentially key-value objects that store the text of the token and what kind of token it is. The value of the Token is an enumeration key-value object that further stores details of the token.
After the input has gone through the lexer, we begin parsing the code in accordance to our above grammar.
If for some odd reason you want to try and use this compiler set up is easy.
Clone the repo into your desired location.
Run javac TinyCompiler.java inside the repo directory.
Run java TinyCompiler "path to your tiny file"
There should be a new file in the repo directory called out.c that contains the compiled code.
Input
Output
