Top level parsing process
fb.bas:fbCompile() is called from the fbc frontend for every input file. Parsing (and compiling) of the file begins here.
fb.bas:fbCompile()
- Open the input .bas
- Start the emitter (ir) (Open the output .asm)
- fbMainBegin() (Build the AST for the implicit main() or static constructor for module-level code)
- fbPreIncludes()
- fbIncludeFile() for every preinclude (found on the fbc command line)
- cProgram()
- fbMainEnd() (Close the implicit main())
- Finish emitting (ir) (Finish generating the .asm and close it)
- Close the input .bas
fb.bas:fbIncludeFile()
- Include file search
- lexPush() (Push a new lexer context to parse this #include file without disturbing the lexer's state in the parent file)
- Open the include file
- cProgram()
- Close the include file
- lexPop() (Restore the lexer state to the parent file)
parser-toplevel.bas:cProgram() is the root of the FB grammar, and parses a file. Here's a short & quick run down of what is done:
- cLine() repeatedly until EOF
- cLabel()
- cStatement()
- Declarations
- UDT declarations, typedefs
- Variables (DIM, VAR, ...)
- Procedure declarations (DECLARE)
- Procedure bodies (SUB, FUNCTION, ...)
- Compounds statements (IF/ELSE, DO/LOOP, EXIT/CONTINUE DO, ...)
- Procedure calls
- Function result assignments
- Quirk statements (special QB rtlib/gfxlib statements)
- ASM blocks
- Assignments
- Procedure pointer calls
(Procs temporarily replace the implicit module level procedure, so any AST nodes go into them instead of the implicit main())
and most of them use cExpression() at some point.
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