som v 4.2a

som 42a is som 4.2 (triple 9 release) with correction to lex that enables it to run in interactive mode.

the next improvement will be 
1)  make print-string to be syscall. print-string in som calls fprintc a lot of times. It should be better to convert som-string to c-string and call fprints once.
2)  write parser generator in som and generate a new parse.som. The goal is to improve som compiler and to have a new application in som.

19 sept 2009

all above are done.  "parse2.som" becomes the new parser. The parser generator is about 700 lines. To compile som v4.2 it tooks som42a noi 2974486.  Use it to compile the benchmark som31 in noi 3363375.  Compare this to som 4.1 compiling som31 in 4798780, and som 4.2 with old parser in 3757236.

    v42a/v41 =  3363375/4798780 = 0.70, speedup 30%
    v42a/v42 =  3363375/3757236 = 0.89, speedup 11%

22 sept 2009
