Re: [Groff] Proposed equation processor additions

[Werner LEMBERG]

> If I understand correctly, you would like the format line to be
> optional,

Yes.

> but if specified to be preceded by the work "col".

Yes.

> As an option, the second format statement above might also be used
> (col "ll").

Mhm, perhaps it is better to use just one the formats.  I don't see a
need to have two syntax forms.  Perhaps we should do a poll which
syntax form is preferable.  Any opinions out there?

I now think that my proposed `col' keyword is redundant.  The
following should do just fine:

  rmatrix {
    "ll"
    { a b }
    { c d }
  }

Have a look at the attached diff of eqn.y which is a first try to
implement my syntax.

> > BTW, could you integrate the rmatrix stuff directly into eqn.y?
> > How much work is it?
> 
> This might be a LOT more work.  I specifically chose to minimize the
> impact of my code on James' work for two reasons:
> 
>       My C++ is somewhere past novice, but not yet at an
>       intermediate stage.  So I thought 'tacking' my code on would
>       ensure that I didn't muck up his.

My C++ isn't that good either :-)  Basically, it shouldn't be that
hard, and I'll assist you if questions arise.

> If you insist, then I'll spend some time on James' code to see how
> it might be done.

Please do so -- and thanks in advance!  There is no need to hurry.

BTW, I see a problem with your proposed `#' comment token: It doesn't
work in in-line equations like $x$.  We have two possibilities:

  1. Disallow `#' in in-line equations.

  2. Use, say, `#{' and `#}' to start and end a comment.  (Are there
     better suggestions for the comment delimiters?)

For item 1 I suggest to handle it directly in function get_token (in
lex.cpp) -- have a look at the similar code in the pic preprocessor
for comparison.

For item 2 (which I prefer) it is very simple to add a rule to eqn.y
since we no longer are limited to a single line.


    Werner


======================================================================


--- eqn.y       2004-04-08 22:43:23.000000000 +0200
+++ eqn.y.new   2005-02-22 10:37:21.115271536 +0100
@@ -1,4 +1,5 @@
-/* Copyright (C) 1989, 1990, 1991, 1992, 2004 Free Software Foundation, Inc.
+/* Copyright (C) 1989, 1990, 1991, 1992, 2004, 2005
+   Free Software Foundation, Inc.
      Written by James Clark (address@hidden)
 
 This file is part of groff.
@@ -33,8 +34,10 @@
        box *b;
        pile_box *pb;
        matrix_box *mb;
+       rmatrix_box *rb;
        int n;
        column *col;
+       row *row;
 }
 
 %token OVER
@@ -67,6 +70,7 @@
 %token DOWN
 %token UP
 %token MATRIX
+%token RMATRIX
 %token COL
 %token LCOL
 %token RCOL
@@ -103,7 +107,7 @@
 
 %right LEFT
 %left RIGHT
-%right LPILE RPILE CPILE PILE TEXT QUOTED_TEXT MATRIX MARK LINEUP '^' '~' '\t' 
'{' SPLIT NOSPLIT
+%right LPILE RPILE CPILE PILE TEXT QUOTED_TEXT MATRIX RMATRIX MARK LINEUP '^' 
'~' '\t' '{' SPLIT NOSPLIT
 %right FROM TO
 %left SQRT OVER SMALLOVER
 %right SUB SUP
@@ -117,6 +121,8 @@
 %type <pb> pile_element_list pile_arg
 %type <mb> column_list
 %type <col> column column_arg column_element_list
+%type <rb> row_list
+%type <row> row row_element_list
 
 %%
 top:
@@ -214,6 +220,10 @@
                { $2->set_alignment(CENTER_ALIGN); $$ = $2; }
        | MATRIX '{' column_list '}'
                { $$ = $3; }
+       | RMATRIX '{' QUOTED_TEXT row_list '}'
+               { $$ = convert_rmatrix($3, $4); }
+       | RMATRIX '{' row_list '}'
+               { $$ = convert_rmatrix(0, $3); }
        | LEFT delim equation RIGHT delim
                { $$ = make_delim_box($2, $3, $5); }
        | LEFT delim equation
@@ -312,6 +322,25 @@
                { $2->set_alignment(CENTER_ALIGN); $$ = $2; }
        ;
 
+row_list:
+       row
+               { $$ = new rmatrix_box($1); }
+       | row_list row
+               { $1->append($2); $$ = $1; }
+       ;
+
+row_element_list:
+       equation
+               { $$ = new row($1); }
+       | row_element_list equation
+               { $1->append($2); $$ = $1; }
+       ;
+
+row:
+       '{' row_element_list '}'
+               { $$ = $2; }
+       ;
+
 text:  TEXT
                { $$ = $1; }
        | QUOTED_TEXT