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## Last modification: 8/3/00 by akp
4
## Originally written by Daniel Martin, Dept of Math, John Hopkins
5
## Additions and modifications were made by James Martino, Dept of Math, John Hopkins
6
## Additions and modifications were made by Arnold Pizer, Dept of Math, Univ of Rochester
7
 
8
#use Data::Dumper;
9
 
10
package AlgParser;
11
use HTML::Entities;
12
 
13
%close = ();
14
 
15
sub new {
16
  my $package = shift;
17
  my (%ret);
18
  $ret{string} = "";
19
  $ret{posarray} = [];
20
  $ret{parseerror} = "";
21
  $ret{parseresult} = [];
22
  bless \%ret, $package;
23
  return \%ret;
24
}
25
 
26
sub inittokenizer {
27
  my($self, $string) = @_;
28
  $self->{string} =~ m/\G.*$/g;
29
  $self->{string} = undef;
30
  $self->{string} = $string;
31
  $self->{string} =~ m/\G.*$/g;
32
  $self->{string} =~ m/^/g;
33
}
34
 
35
$close{'{'} = '}';
36
$close{'['} = ']';
37
$close{'('} = ')';
38
 
39
$binoper3 = '(?:\\^|\\*\\*)';
40
$binoper2 = '[/*_,]';
41
$binoper1 = '[-+=><%!#]';
42
$openparen = '[{(\\[]';
43
$closeparen = '[})\\]]';
44
$varname = '[A-Za-z](?:_[0-9]+)?';
45
$specialvalue = '(?:e|pi|da|db|dc|de|df|dg|dh|di|dj|dk|dl|dm|dn|do|dp|dq|dr|ds|dt|du|dv|dw|dx|dy|dz|infty|alpha|bita|gamma|zita|thita|iota|kappa|lambda|mu|nu|xi|rho|sigma|tau|phi|chi|psi|omega|zepslon|zdelta|xeta|zupslon|zeroplace)';
46
$numberplain = '(?:\d+(?:\.\d*)?|\.\d+)';
47
$numberE = '(?:' . $numberplain . 'E[-+]?\d+)';
48
$number = '(?:' . $numberE . '|' . $numberplain . ')';
49
#
50
#  DPVC -- 2003/03/31
51
#       added missing trig and inverse functions
52
#
53
#$trigfname = '(?:cosh|sinh|tanh|cot|(?:a(?:rc)?)?cos|(?:a(?:rc)?)?sin|' .
54
#    '(?:a(?:rc)?)?tan|sech?)';
55
$trigfname = '(?:(?:a(?:rc)?)?(?:sin|cos|tan|sec|csc|cot)h?)';
56
#
57
#  End DPVC
58
#
59
$otherfunc = '(?:exp|abs|logten|log|ln|sqrt|sgn|step|fact|int|lim|fun[a-zA-Z])';
60
$funcname = '(?:' . $otherfunc . '|' . $trigfname . ')';
61
 
62
$tokenregexp = "(?:($binoper3)|($binoper2)|($binoper1)|($openparen)|" .
63
    "($closeparen)|($funcname)|($specialvalue)|($varname)|" .
64
    "($numberE)|($number))";
65
 
66
sub nexttoken {
67
  my($self) = shift;
68
  $self->{string} =~ m/\G\s+/gc;
69
  my($p1) = pos($self->{string}) || 0;
70
  if(scalar($self->{string} =~ m/\G$tokenregexp/gc)) {
71
        push @{$self->{posarray}}, [$p1, pos($self->{string})];
72
        if (defined($1)) {return ['binop3',  $1];}
73
        if (defined($2)) {return ['binop2',  $2];}
74
        if (defined($3)) {return ['binop1',  $3];}
75
        if (defined($4)) {return ['openp',   $4];}
76
        if (defined($5)) {return ['closep',  $5];}
77
        if (defined($6)) {return ['func1',   $6];}
78
        if (defined($7)) {return ['special', $7];}
79
        if (defined($8)) {return ['varname', $8];}
80
        if (defined($9)) {return ['numberE', $9];}
81
        if (defined($10)) {return ['number', $10];}
82
  }
83
  else {
84
    push @{$self->{posarray}}, [$p1, undef];
85
    return undef;
86
  }
87
}
88
 
89
sub parse {
90
  my $self = shift;
91
  $self->{parseerror} = "";
92
  $self->{posarray} = [];
93
  $self->{parseresult} = ['top', undef];
94
  my (@backtrace) = (\$self->{parseresult});
95
  my (@pushback) = ();
96
 
97
  my $currentref = \$self->{parseresult}->[1];
98
  my $curenttok;
99
 
100
  my $sstring = shift;
101
  $self->inittokenizer($sstring);
102
  $currenttok = $self->nexttoken;
103
  if (!$currenttok) {
104
    if ($self->{string} =~ m/\G$/g) {
105
      return $self->error("empty");
106
    } else {
107
      my($mark) = pop @{$self->{posarray}};
108
      my $position = 1+$mark->[0];
109
      return $self->error("Illegal character at position $position", $mark);
110
    }
111
  }
112
  # so I can assume we got a token
113
  local $_;
114
  while ($currenttok) {
115
    $_ = $currenttok->[0];
116
    /binop1/ && do {
117
      # check if we have a binary or unary operation here.
118
      if (defined(${$currentref})) {
119
        # binary - walk up the tree until we hit an open paren or the top
120
        while (${$currentref}->[0] !~ /^(openp|top)/) {
121
          $currentref = pop @backtrace;
122
        }
123
        my $index = ((${$currentref}->[0] eq 'top')?1:3);
124
        ${$currentref}->[$index] = ['binop1', $currenttok->[1],
125
                                    ${$currentref}->[$index], undef];
126
        push @backtrace, $currentref;
127
        push @backtrace, \${$currentref}->[$index];
128
        $currentref = \${$currentref}->[$index]->[3];
129
      } else {
130
        # unary
131
        ${$currentref} = ['unop1', $currenttok->[1], undef];
132
        push @backtrace, $currentref;
133
        $currentref = \${$currentref}->[2];
134
      }
135
    };
136
    /binop2/ && do {
137
      if (defined(${$currentref})) {
138
        # walk up the tree until an open paren, the top, binop1 or unop1
139
        # I decide arbitrarily that -3*4 should be parsed as -(3*4)
140
        # instead of as (-3)*4.  Not that it makes a difference.
141
 
142
        while (${$currentref}->[0] !~ /^(openp|top|binop1)/) {
143
          $currentref = pop @backtrace;
144
        }
145
        my $a = ${$currentref}->[0];
146
        my $index = (($a eq 'top')?1:3);
147
        ${$currentref}->[$index] = ['binop2', $currenttok->[1],
148
                                    ${$currentref}->[$index], undef];
149
        push @backtrace, $currentref;
150
        push @backtrace, \${$currentref}->[$index];
151
        $currentref = \${$currentref}->[$index]->[3];
152
      } else {
153
        # Error
154
        my($mark) = pop @{$self->{posarray}};
155
        my $position =1+$mark->[0];
156
        return $self->error("Didn't expect " . $currenttok->[1] .
157
                            " at position $position" , $mark);
158
      }
159
    };
160
    /binop3/ && do {
161
      if (defined(${$currentref})) {
162
        # walk up the tree until we need to stop
163
        # Note that the right-associated nature of ^ means we need to
164
        # stop walking backwards when we hit a ^ as well.
165
        while (${$currentref}->[0] !~ /^(openp|top|binop[123]|unop1)/) {
166
          $currentref = pop @backtrace;
167
        }
168
        my $a = ${$currentref}->[0];
169
        my $index = ($a eq 'top')?1:($a eq 'unop1')?2:3;
170
        ${$currentref}->[$index] = ['binop3', $currenttok->[1],
171
                                    ${$currentref}->[$index], undef];
172
        push @backtrace, $currentref;
173
        push @backtrace, \${$currentref}->[$index];
174
        $currentref = \${$currentref}->[$index]->[3];
175
      } else {
176
        # Error
177
        my($mark) = pop @{$self->{posarray}};
178
        my $position = 1+$mark->[0];
179
        return $self->error("Didn't expect " . $currenttok->[1] .
180
                            " at position $position", $mark);
181
      }
182
    };
183
    /openp/ && do {
184
      if (defined(${$currentref})) {
185
        # we weren't expecting this - must be implicit
186
        # multiplication.
187
        push @pushback, $currenttok;
188
        $currenttok = ['binop2', 'implicit'];
189
        next;
190
      } else {
191
        my($me) = pop @{$self->{posarray}};
192
        ${$currentref} = [$currenttok->[0], $currenttok->[1], $me, undef];
193
        push @backtrace, $currentref;
194
        $currentref = \${$currentref}->[3];
195
      }
196
    };
197
    /func1/ && do {
198
      if (defined(${$currentref})) {
199
        # we weren't expecting this - must be implicit
200
        # multiplication.
201
        push @pushback, $currenttok;
202
        $currenttok = ['binop2', 'implicit'];
203
        next;
204
      } else {
205
        # just like a unary operator
206
        ${$currentref} = [$currenttok->[0], $currenttok->[1], undef];
207
        push @backtrace, $currentref;
208
        $currentref = \${$currentref}->[2];
209
      }
210
    };
211
    /closep/ && do {
212
      if (defined(${$currentref})) {
213
        # walk up the tree until we need to stop
214
        while (${$currentref}->[0] !~ /^(openp|top)/) {
215
          $currentref = pop @backtrace;
216
        }
217
        my $a = ${$currentref}->[0];
218
        if ($a eq 'top') {
219
          my($mark) = pop @{$self->{posarray}};
220
          my $position = 1+$mark->[0];
221
          return $self->error("Unmatched close " . $currenttok->[1] .
222
                              " at position $position", $mark);
223
        } elsif ($close{${$currentref}->[1]} ne $currenttok->[1]) {
224
          my($mark) = pop @{$self->{posarray}};
225
          my $position = 1+$mark->[0];
226
          return $self->error("Mismatched parens at position $position"
227
                              , ${$currentref}->[2], $mark);
228
        } else {
229
          ${$currentref}->[0] = 'closep';
230
          ${$currentref}->[2] = pop @{${$currentref}};
231
        }
232
      } else {
233
        # Error - something like (3+4*)
234
        my($mark) = pop @{$self->{posarray}};
235
        my $position = 1+$mark->[0];
236
        return $self->error("Premature close " . $currenttok->[1] .
237
                            " at position $position", $mark);
238
      }
239
    };
240
    /special|varname|numberE?/ && do {
241
      if (defined(${$currentref})) {
242
        # we weren't expecting this - must be implicit
243
        # multiplication.
244
        push @pushback, $currenttok;
245
        $currenttok = ['binop2', 'implicit'];
246
        next;
247
      } else {
248
        ${$currentref} = [$currenttok->[0], $currenttok->[1]];
249
      }
250
    };
251
    if (@pushback) {
252
      $currenttok = pop @pushback;
253
    } else {
254
      $currenttok = $self->nexttoken;
255
    }
256
  }
257
  # ok, we stopped parsing.  Now we need to see why.
258
  if ($self->{parseresult}->[0] eq 'top') {
259
    $self->{parseresult} = $self->arraytoexpr($self->{parseresult}->[1]);
260
  } else {
261
    return $self->error("Internal consistency error; not at top when done");
262
  }
263
  if ($self->{string} =~ m/\G\s*$/g) {
264
    if (!defined(${$currentref})) {
265
      $self->{string} .= " ";
266
      return $self->error("I was expecting more at the end of the line",
267
                        [length($self->{string})-1, length($self->{string})]);
268
    } else {
269
      # check that all the parens were closed
270
      while (@backtrace) {
271
        $currentref = pop @backtrace;
272
        if (${$currentref}->[0] eq 'openp') {
273
          my($mark) = ${$currentref}->[2];
274
          my $position = 1+$mark->[0];
275
          return $self->error("Unclosed parentheses beginning at position $position"
276
                         , $mark);
277
        }
278
      }
279
      # Ok, we must really have parsed something
280
      return $self->{parseresult};
281
    }
282
  } else {
283
      my($mark) = pop @{$self->{posarray}};
284
      my $position = 1+$mark->[0];
285
      return $self->error("Illegal character at position $position",$mark);
286
  }
287
}
288
 
289
sub arraytoexpr {
290
  my ($self) = shift;
291
  return Expr->fromarray(@_);
292
}
293
 
294
sub error {
295
  my($self, $errstr, @markers) = @_;
296
#  print STDERR Data::Dumper->Dump([\@markers],
297
#                                  ['$markers']);
298
  $self->{parseerror} = $errstr;
299
  my($htmledstring) = '<tt class="parseinput">';
300
  my($str) = $self->{string};
301
#  print STDERR Data::Dumper->Dump([$str], ['$str']);
302
  my($lastpos) = 0;
303
  $str =~ s/ /\240/g;
304
  while(@markers) {
305
    my($ref) = shift @markers;
306
    my($pos1) = $ref->[0];
307
    my($pos2) = $ref->[1];
308
    if (!defined($pos2)) {$pos2 = $pos1+1;}
309
    $htmledstring .= encode_entities(substr($str,$lastpos,$pos1-$lastpos)) .
310
           '<b class="parsehilight">' .
311
           encode_entities(substr($str,$pos1,$pos2-$pos1)) .
312
           '</b>';
313
    $lastpos = $pos2;
314
  }
315
#  print STDERR Data::Dumper->Dump([$str, $htmledstring, $lastpos],
316
#                                  ['$str', '$htmledstring', '$lastpos']);
317
  $htmledstring .= encode_entities(substr($str,$lastpos));
318
  $htmledstring .= '</tt>';
319
#  $self->{htmlerror} = '<p class="parseerr">' . "\n" .
320
#                       '<span class="parsedesc">' .
321
#                       encode_entities($errstr) . '</span><br>' . "\n" .
322
#                       $htmledstring . "\n" . '</p>' . "\n";
323
  $self->{htmlerror} =  $htmledstring ;
324
  $self->{htmlerror} =  'empty' if $errstr eq 'empty';
325
  $self->{error_msg} = $errstr;
326
 
327
#  warn $errstr . "\n";
328
  return undef;
329
}
330
 
331
sub tostring {
332
  my ($self) = shift;
333
  return $self->{parseresult}->tostring(@_);
334
}
335
 
336
sub tolatex {
337
  my ($self) = shift;
338
  return $self->{parseresult}->tolatex(@_);
339
}
340
 
341
sub tolatexstring { return tolatex(@_);}
342
 
343
sub exprtolatexstr {
344
  return exprtolatex(@_);
345
}
346
 
347
sub exprtolatex {
348
  my($expr) = shift;
349
  my($exprobj);
350
  if ((ref $expr) eq 'ARRAY') {
351
    $exprobj = Expr->new(@$expr);
352
  } else {
353
    $exprobj = $expr;
354
  }
355
  return $exprobj->tolatex();
356
}
357
 
358
sub exprtostr {
359
  my($expr) = shift;
360
  my($exprobj);
361
  if ((ref $expr) eq 'ARRAY') {
362
    $exprobj = Expr->new(@$expr);
363
  } else {
364
    $exprobj = $expr;
365
  }
366
  return $exprobj->tostring();
367
}
368
 
369
sub normalize {
370
  my ($self, $degree) = @_;
371
  $self->{parseresult} = $self->{parseresult}->normalize($degree);
372
}
373
 
374
sub normalize_expr {
375
  my($expr, $degree) = @_;
376
  my($exprobj);
377
  if ((ref $expr) eq 'ARRAY') {
378
    $exprobj = Expr->new(@$expr);
379
  } else {
380
    $exprobj = $expr;
381
  }
382
  return $exprobj->normalize($degree);
383
}
384
 
385
package AlgParserWithImplicitExpand;
386
@ISA=qw(AlgParser);
387
 
388
sub arraytoexpr {
389
  my ($self) = shift;
390
  my ($foo) = ExprWithImplicitExpand->fromarray(@_);
391
# print STDERR Data::Dumper->Dump([$foo],['retval']);
392
  return $foo;
393
}
394
 
395
package Expr;
396
 
397
sub new {
398
  my($class) = shift;
399
  my(@args) = @_;
400
  my($ret) = [@args];
401
  return (bless $ret, $class);
402
}
403
 
404
sub head {
405
  my($self) = shift;
406
  return ($self->[0]);
407
}
408
 
409
 
410
sub normalize {
411
#print STDERR "normalize\n";
412
#print STDERR Data::Dumper->Dump([@_]);
413
 
414
  my($self, $degree) = @_;
415
  my($class) = ref $self;
416
  $degree = $degree || 0;
417
  my($type, @args) = @$self;
418
  local $_;
419
  $_ = $type;
420
  my ($ret) = [$type, @args];
421
 
422
 
423
  if(/closep/) {
424
    $ret = $args[1]->normalize($degree);
425
  } elsif (/unop1/) {
426
    $ret = $class->new($type, $args[0], $args[1]->normalize($degree));
427
  } elsif (/binop/) {
428
    $ret = $class->new($type, $args[0], $args[1]->normalize($degree),
429
                             $args[2]->normalize($degree));
430
  } elsif (/func1/) {
431
    $args[0] =~ s/^arc/a/;
432
    $ret = $class->new($type, $args[0], $args[1]->normalize($degree));
433
  }
434
 
435
 
436
  if ($degree < 0) {return $ret;}
437
 
438
 
439
  ($type, @args) = @$ret;
440
  $ret = $class->new($type, @args);
441
  $_ = $type;
442
  if (/binop1/ && ($args[2]->[0] =~ 'unop1')) {
443
    my($h1, $h2) = ($args[0], $args[2]->[1]);
444
    my($s1, $s2) = ($h1 eq '-', $h2 eq '-');
445
    my($eventual) = ($s1==$s2);
446
    if ($eventual) {
447
      $ret = $class->new('binop1', '+', $args[1], $args[2]->[2] );
448
    } else {
449
      $ret = $class->new('binop1', '-', $args[1], $args[2]->[2] );
450
    }
451
  } elsif (/binop2/ && ($args[1]->[0] =~ 'unop1')) {
452
    $ret = $class->new('unop1', '-',
453
                       $class->new($type, $args[0], $args[1]->[2],
454
                                   $args[2])->normalize($degree) );
455
  } elsif (/binop[12]/ && ($args[2]->[0] eq $type) &&
456
                          ($args[0] =~ /[+*]/)) {
457
# Remove frivolous right-association
458
# For example, fix 3+(4-5) or 3*(4x)
459
    $ret = $class->new($type, $args[2]->[1],
460
                       $class->new($type, $args[0], $args[1],
461
                                   $args[2]->[2])->normalize($degree),
462
                       $args[2]->[3]);
463
  } elsif (/unop1/ && ($args[0] eq '+')) {
464
    $ret = $args[1];
465
  } elsif (/unop1/ && ($args[1]->[0] =~ 'unop1')) {
466
    $ret = $args[1]->[2];
467
  }
468
  if ($degree > 0) {
469
  }
470
  return $ret;
471
}
472
 
473
sub tostring {
474
# print STDERR "Expr::tostring\n";
475
# print STDERR Data::Dumper->Dump([@_]);
476
  my($self) = shift;
477
  my($type, @args) = @$self;
478
  local $_;
479
  $_ = $type;
480
  /binop1/ && do {
481
    my ($p1, $p2) = ('','');
482
    if ($args[2]->[0] eq 'binop1') {($p1,$p2)=qw{ ( ) };}
483
    return ($args[1]->tostring() . $args[0] . $p1 .
484
            $args[2]->tostring() . $p2);
485
  };
486
  /unop1/ && do {
487
    my ($p1, $p2) = ('','');
488
    if ($args[1]->[0] =~ /binop1/) {($p1,$p2)=qw{ ( ) };}
489
    return ($args[0] . $p1 . $args[1]->tostring() . $p2);
490
  };
491
  /binop2/ && do {
492
    my ($p1, $p2, $p3, $p4)=('','','','');
493
    if ($args[0] =~ /implicit/) {$args[0] = ' ';}
494
    if ($args[1]->[0] =~ /binop1/) {($p1,$p2)=qw{ ( ) };}
495
#    if ($args[2]->[0] =~ /binop[12]/) {($p3,$p4)=qw{ ( ) };}
496
    if ($args[2]->[0] =~ /binop[12]|unop1/) {($p3,$p4)=qw{ ( ) };}
497
    return ($p1 . $args[1]->tostring() . $p2 . $args[0] . $p3 .
498
            $args[2]->tostring() . $p4);
499
  };
500
  /binop3/ && do {
501
    my ($p1, $p2, $p3, $p4)=('','','','');
502
#    if ($args[1]->[0] =~ /binop[123]|numberE/) {($p1,$p2)=qw{ ( ) };}
503
    if ($args[1]->[0] =~ /binop[123]|unop1|numberE/) {($p1,$p2)=qw{ ( ) };}
504
#    if ($args[2]->[0] =~ /binop[12]|numberE/) {($p3,$p4)=qw{ ( ) };}
505
    if ($args[2]->[0] =~ /binop[12]|unop1|numberE/) {($p3,$p4)=qw{ ( ) };}
506
    return ($p1 . $args[1]->tostring() . $p2 . $args[0] . $p3 .
507
            $args[2]->tostring() . $p4);
508
  };
509
  /func1/ && do {
510
    return ($args[0] . '(' . $args[1]->tostring() . ')');
511
  };
512
  /special|varname|numberE?/ && return $args[0];
513
  /closep/ && do {
514
    my(%close) = %AlgParser::close;
515
 
516
 
517
 
518
    return ($args[0] . $args[1]->tostring() . $close{$args[0]});
519
  };
520
}
521
 
522
sub tolatex {
523
  my($self) = shift;
524
  my($type, @args) = @$self;
525
  local $_;
526
  $_ = $type;
527
  /binop1/ && do {
528
    my ($p1, $p2) = ('','');
529
    if ($args[2]->[0] eq 'binop1') {($p1,$p2)=qw{ \left( \right) };}
530
    return ($args[1]->tolatex() . $args[0] . $p1 .
531
            $args[2]->tolatex() . $p2);
532
  };
533
  /unop1/ && do {
534
    my ($p1, $p2) = ('','');
535
    if ($args[1]->[0] =~ /binop1/) {($p1,$p2)=qw{ \left( \right) };}
536
    return ($args[0] . $p1 . $args[1]->tolatex() . $p2);
537
  };
538
  /binop2/ && do {
539
    my ($p1, $p2, $p3, $p4) = ('','','','');
540
    if ($args[0] =~ /implicit/) {
541
      if ( (($args[1]->head eq qq(number)) &&
542
            ($args[2]->head eq qq(number))) ||
543
           (($args[1]->head eq qq(binop2)) &&
544
            ($args[1]->[2]->head eq qq(number))) ) {
545
        $args[0] = '\\,';
546
      } else {
547
        $args[0] = ' ';
548
      }
549
    }
550
    if ($args[1]->[0] =~ /binop1|numberE/)
551
      {($p1,$p2)=qw{ \left( \right) };}
552
 #   if ($args[2]->[0] =~ /binop[12]|numberE/)
553
        if ($args[2]->[0] =~ /binop[12]|numberE|unop1/)
554
      {($p3,$p4)=qw{ \left( \right) };}
555
    if ($args[0] eq '/'){
556
#   return('\frac{' . $p1 . $args[1]->tolatex() . $p2 . '}'.
557
#               '{' . $p3 . $args[2]->tolatex() . $p4 . '}' );
558
        return('\frac{' . $args[1]->tolatex() . '}'.
559
               '{' . $args[2]->tolatex() . '}' );
560
    }
561
    else{
562
    return ($p1 . $args[1]->tolatex() . $p2 . $args[0] . $p3 .
563
            $args[2]->tolatex() . $p4);
564
    }
565
  };
566
  /binop3/ && do {
567
    my ($p1, $p2, $p3, $p4)=('','','','');
568
#    if ($args[1]->[0] =~ /binop[123]|numberE/) {($p1,$p2)=qw{ \left( \right) };}
569
  if ($args[1]->[0] =~ /binop[123]|unop1|numberE/) {($p1,$p2)=qw{ \left( \right) };}
570
# Not necessary in latex
571
#   if ($args[2]->[0] =~ /binop[12]/) {($p3,$p4)=qw{ \left( \right) };}
572
    return ($p1 . $args[1]->tolatex() . $p2 . "^{" . $p3 .
573
            $args[2]->tolatex() . $p4 . "}");
574
  };
575
  /func1/ && do {
576
      my($p1,$p2);
577
      if($args[0] eq "sqrt"){($p1,$p2)=qw{ \left{ \right} };}
578
      else {($p1,$p2)=qw{ \left( \right) };}
579
 
580
      #
581
      #  DPVC -- 2003/03/31
582
      #       added missing trig functions
583
      #
584
      #$specialfunc = '(?:abs|logten|asin|acos|atan|sech|sgn|step|fact)';
585
      $specialfunc = '(?:abs|logten|a(?:sin|cos|tan|sec|csc|cot)h?|sgn|step|fact)';
586
      #
587
      #  End DPVC
588
      #
589
 
590
      if ($args[0] =~ /$specialfunc/) {
591
         return ('\mbox{' . $args[0] .'}'. $p1 . $args[1]->tolatex() . $p2);
592
      }
593
      else {
594
        return ('\\' . $args[0] . $p1 . $args[1]->tolatex() . $p2);
595
      }
596
  };
597
  /special/ && do {
598
    if ($args[0] eq 'pi') {return '\pi';} else {return $args[0];}
599
  };
600
  /varname|(:?number$)/ && return $args[0];
601
  /numberE/ && do {
602
    $args[0] =~ m/($AlgParser::numberplain)E([-+]?\d+)/;
603
    return ($1 . '\times 10^{' . $2 . '}');
604
  };
605
  /closep/ && do {
606
    my($backslash) = '';
607
    my(%close) = %AlgParser::close;
608
    if ($args[0] eq '{') {$backslash = '\\';}
609
#This is for editors to match: }
610
    return ('\left' . $backslash . $args[0] . $args[1]->tolatex() .
611
            '\right' . $backslash . $close{$args[0]});
612
  };
613
}
614
 
615
sub fromarray {
616
  my($class) = shift;
617
  my($expr) = shift;
618
  if ((ref $expr) ne qq{ARRAY}) {
619
    die "Program error; fromarray not passed an array ref.";
620
  }
621
  my($type, @args) = @$expr;
622
  foreach my $i (@args) {
623
    if (ref $i) {
624
      $i = $class->fromarray($i);
625
    }
626
  }
627
  return $class->new($type, @args);
628
}
629
 
630
package ExprWithImplicitExpand;
631
@ISA=qw(Expr);
632
 
633
 
634
sub tostring {
635
# print STDERR "ExprWIE::tostring\n";
636
# print STDERR Data::Dumper->Dump([@_]);
637
  my ($self) = shift;
638
 
639
  my($type, @args) = @$self;
640
 
641
  if (($type eq qq(binop2)) && ($args[0] eq qq(implicit))) {
642
    my ($p1, $p2, $p3, $p4)=('','','','');
643
    if ($args[1]->head =~ /binop1/) {($p1,$p2)=qw{ ( ) };}
644
#    if ($args[2]->head =~ /binop[12]/) {($p3,$p4)=qw{ ( ) };}
645
    if ($args[2]->head =~ /binop[12]|unop1/) {($p3,$p4)=qw{ ( ) };}
646
    return ($p1 . $args[1]->tostring() . $p2 . '*' . $p3 .
647
            $args[2]->tostring() . $p4);
648
  } else {
649
    return $self->SUPER::tostring(@_);
650
  }
651
}