vm and compiler mode

set M[lexmode_ads]  to communicate between compiler and lex (in vm) whether to lex one line and return to caller (line mode) or to lex until eof (batch mode). Compiler sets this mode according to its mode of use (interactive or compile).  "loadfile" needs to be in batch mode.

other consideration: "cmode" in compiler is used only in "genex" to do "updatesym".  It is used to distinguish between genex during immediate line and in define function.  This can be achieved using "currentf = 0".  So "cmode" is eliminated.

Now there are two mode-things: use_mode and lexmode.  use_mode is what user start vm (interactive, compile, execute). It conveys this information to compiler by M[MODE_ADS].  lexmode is already explained above.

25 Oct 2009
