On 27 Jan 2009, at 01:14, Alex Ryu wrote:
I have a series of large arrays of floating point data. "Attached"
to each
array is a smaller array of integers, call it c. What I would like
to do
is perform operations on c of this nature:
if c[1] < 54 and c[13] != 7 then c[3] = 16, etc. These instructions
will be
contained in a char buffer, which I think I can use as the input to
lex.
After the operations are made, then I just want to output/write to
disk the
arrays. Is this possible using lex and bison? It seems like it
should be,
but I can't quite find a way. How do I make yyparse() "see" the
arrays?
Would I have to directly modify the output of bison? Thanks for any
help
you can provide.
Outline:
Say c = {1,3,5,9,-8}, and instructs = "if c[1] < 54 and c[0] != 7
then c[3]
= 16" Then I would want yyparse() to change c to {1,3,5,16,-8}.
Remember
that we have a lot of "c's", so I suppose one would make the
substitution 1
for c[0], etc, before passing to yylex().
Bison and Flex are used to construct compilers/interpreters, from a
small calculators as in the Bison manual, to full grown computer
languages.
Why can't or would not want you use a for an existing language, like C/
C++, or Hugs or GHC for a language like Haskell <http://haskell.org>
which admit FFI (Foreign Function Interfaces) - that might save you
time, even if you want to take the long road of constructing.
Otherwise, external is typically called from the actions - so you make
sure your .y file ha a #include to your code header, and inserts the
actions into the headers. If you want to be able to do definitions,
make a lookup table that the lexer can see. If you want to do loops
and code jumps, build closures that can be executed after the parsing.
Hans
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