Philip Kendall - CheckBasic

2002 July 29: if you are thinking of doing anything with CheckBasic, please consider looking at Basic instead, which is a BASIC interpreter. Adding syntax checking would be very trivial.

CheckBasic is a program which will check that a Spectrum BASIC listing in a text file is valid BASIC. This was inspired by a request on comp.sys.sinclair for a program to make error-checking OCR'd scanned listings from magazines easier. CheckBasic is currently very much in the alpha stage of development, and there are probably a whole load of bugs left in it. Known bugs/problems include:

Quotes inside strings aren't recognised correctly (this is just me being lazy in the lexical analyser)
Variable names with spaces in aren't recognised (again, me being lazy)
Variable names which are the same as keywords aren't recognised; this is a more fundamental problem, and one which is never going to be completely solved (consider a variable called `RND')
Only the standard 48K machines commands are recognised (no IF1/128K/+2A/+3 commands)

Improvements for version 0.03:

Statements of the form PRINT #n are now accepted.
The `Parse error' messages are now sent to stdout, rather than stderr.

The input for CheckBasic is fairly simple: a plain text file, with one BASIC line per line of the text file. The only vaguely non-obvious conversion from the Speccy's character set to the PC's is the exponentiation character (up arrow, symbol shift+H, character 94 or 5Eh) is mapped to the caret (^). All input is read from standard input, whilst all normal output is to standard output, with errors going to standard error.

CheckBasic is written in Bison (I think it should work with yacc) and C, and is available for download in two forms:

Source (28999 bytes)
Source and a DJGPP-compiled DOS binary (76534 bytes).

The DOS executable will require a DPMI server to run; see here for details.

Please note that this program is covered by the GNU General Public License. If you do not accept these conditions, please do not download this program.