File:  [LON-CAPA] / loncom / homework / math_parser / ENode.pm
Revision 1.3: download - view: text, annotated - select for diffs
Tue Jun 30 17:42:14 2015 UTC (8 years, 10 months ago) by damieng
Branches: MAIN
CVS tags: HEAD
math parser: changed syntax to avoid compatibility problems with Perl 5.8.8

    1: # The LearningOnline Network with CAPA - LON-CAPA
    2: # Parsed tree node
    3: #
    4: # Copyright (C) 2014 Michigan State University Board of Trustees
    5: #
    6: # This program is free software: you can redistribute it and/or modify
    7: # it under the terms of the GNU General Public License as published by
    8: # the Free Software Foundation, either version 3 of the License, or
    9: # (at your option) any later version.
   10: #
   11: # This program is distributed in the hope that it will be useful,
   12: # but WITHOUT ANY WARRANTY; without even the implied warranty of
   13: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   14: # GNU General Public License for more details.
   15: #
   16: # You should have received a copy of the GNU General Public License
   17: # along with this program. If not, see <http://www.gnu.org/licenses/>.
   18: #
   19: 
   20: ##
   21: # Parsed tree node. ENode.toMathML(hcolors) contains the code for the transformation into MathML.
   22: ##
   23: package Apache::math_parser::ENode;
   24: 
   25: use strict;
   26: use warnings;
   27: use utf8;
   28: 
   29: use Switch 'Perl6';
   30: 
   31: use aliased 'Apache::math_parser::CalcException';
   32: use aliased 'Apache::math_parser::Operator';
   33: use aliased 'Apache::math_parser::ParseException';
   34: use aliased 'Apache::math_parser::QMatrix';
   35: use aliased 'Apache::math_parser::Quantity';
   36: use aliased 'Apache::math_parser::QVector';
   37: use aliased 'Apache::math_parser::QInterval';
   38: use aliased 'Apache::math_parser::QIntervalUnion';
   39: use aliased 'Apache::math_parser::QSet';
   40: use aliased 'Apache::math_parser::Units';
   41: 
   42: use enum qw(UNKNOWN NAME NUMBER OPERATOR FUNCTION VECTOR INTERVAL SET SUBSCRIPT);
   43: use enum qw(NOT_AN_INTERVAL OPEN_OPEN OPEN_CLOSED CLOSED_OPEN CLOSED_CLOSED);
   44: 
   45: ##
   46: # @param {integer} type - UNKNOWN | NAME | NUMBER | OPERATOR | FUNCTION | VECTOR | INTERVAL | SET | SUBSCRIPT
   47: # @param {Operator} op - The operator
   48: # @param {string} value - Node value as a string, undef for type VECTOR
   49: # @param {ENode[]} children - The children nodes, only for types OPERATOR, FUNCTION, VECTOR, INTERVAL, SET, SUBSCRIPT
   50: # @param {interval_type} - The interval type, NOT_AN_INTERVAL | OPEN_OPEN | OPEN_CLOSED | CLOSED_OPEN | CLOSED_CLOSED
   51: ##
   52: sub new {
   53:     my ($class, $type, $op, $value, $children, $interval_type) = @_;
   54:     if (!defined $interval_type) {
   55:         $interval_type = NOT_AN_INTERVAL;
   56:     }
   57:     my $self = {
   58:         _type => $type,
   59:         _op => $op,
   60:         _value => $value,
   61:         _children => $children,
   62:         _interval_type => $interval_type,
   63:     };
   64:     bless $self, $class;
   65:     return $self;
   66: }
   67: 
   68: # Attribute helpers
   69: 
   70: ##
   71: # Node type
   72: # @returns {int} UNKNOWN | NAME | NUMBER | OPERATOR | FUNCTION | VECTOR | INTERVAL | SET | SUBSCRIPT
   73: ##
   74: sub type {
   75:     my $self = shift;
   76:     return $self->{_type};
   77: }
   78: 
   79: ##
   80: # Operator
   81: # @returns {Operator}
   82: ##
   83: sub op {
   84:     my $self = shift;
   85:     return $self->{_op};
   86: }
   87: 
   88: ##
   89: # Node value as a string, undef for type VECTOR.
   90: # @returns {string}
   91: ##
   92: sub value {
   93:     my $self = shift;
   94:     return $self->{_value};
   95: }
   96: 
   97: ##
   98: # The children nodes, only for types OPERATOR, FUNCTION, VECTOR, INTERVAL, SET, SUBSCRIPT
   99: # @returns {ENode[]}
  100: ##
  101: sub children {
  102:     my $self = shift;
  103:     return $self->{_children};
  104: }
  105: 
  106: ##
  107: # The interval type, NOT_AN_INTERVAL | OPEN_OPEN | OPEN_CLOSED | CLOSED_OPEN | CLOSED_CLOSED
  108: # @returns {int}
  109: ##
  110: sub interval_type {
  111:     my $self = shift;
  112:     return $self->{_interval_type};
  113: }
  114: 
  115: 
  116: ##
  117: # Returns the node as a string, for debug
  118: # @returns {string}
  119: ##
  120: sub toString {
  121:     my ( $self ) = @_;
  122:     my $s = '(';
  123:     given ($self->type) {
  124:         when (UNKNOWN) { $s .= "UNKNOWN"; }
  125:         when (NAME) { $s .= "NAME"; }
  126:         when (NUMBER) { $s .= "NUMBER"; }
  127:         when (OPERATOR) { $s .= "OPERATOR"; }
  128:         when (FUNCTION) { $s .= "FUNCTION"; }
  129:         when (VECTOR) { $s .= "VECTOR"; }
  130:         when (INTERVAL) { $s .= "INTERVAL"; }
  131:         when (SET) { $s .= "SET"; }
  132:         when (SUBSCRIPT) { $s .= "SUBSCRIPT"; }
  133:     }
  134:     if (defined $self->op) {
  135:         $s .= " '" . $self->op->id . "'";
  136:     }
  137:     if (defined $self->value) {
  138:         $s .= " '" . $self->value . "'";
  139:     }
  140:     if (defined $self->{_children}) {
  141:         $s .= ' [';
  142:         for (my $i = 0; $i < scalar(@{$self->children}); $i++) {
  143:             $s .= $self->children->[$i]->toString();
  144:             if ($i != scalar(@{$self->children}) - 1) {
  145:                 $s .= ',';
  146:             }
  147:         }
  148:         $s .= ']';
  149:     }
  150:     if (defined $self->interval_type) {
  151:         $s .= " " . $self->interval_type;
  152:     }
  153:     $s.= ')';
  154:     return $s;
  155: }
  156: 
  157: ##
  158: # Evaluates the node, returning a quantity or an object from a more complex class using quantities as base components.
  159: # Can throw a CalcException if a result cannot be calculated.
  160: # @param {CalcEnv} env - Calculation environment.
  161: # @returns {Quantity|QVector|QMatrix|QSet|QInterval|QIntervalUnion}
  162: ##
  163: sub calc {
  164:     my ( $self, $env ) = @_;
  165:     
  166:     given ($self->type) {
  167:         when (UNKNOWN) {
  168:             die CalcException->new("Unknown node type: [_1].", $self->value);
  169:         }
  170:         when (NAME) {
  171:             my $name = $self->value;
  172:             if ($name =~ /^inf$/i) {
  173:                 return Quantity->new(9**9**9);
  174:             } elsif ($name =~ /^nan$/i) {
  175:                 return Quantity->new(-sin(9**9**9));
  176:             }
  177:             if ($env->unit_mode) {
  178:                 my $cst = $env->getConstant($name);
  179:                 if (defined $cst) {
  180:                     return $cst;
  181:                 }
  182:                 return $env->convertToSI($name);
  183:             } else {
  184:                 my $q = $env->getVariable($name);
  185:                 if (!defined $q) {
  186:                     my $cst = $env->getConstant($name);
  187:                     if (defined $cst) {
  188:                         return $cst;
  189:                     }
  190:                     die CalcException->new("Variable has undefined value: [_1].", $name);
  191:                 }
  192:                 return $q;
  193:             }
  194:         }
  195:         when (NUMBER) {
  196:             return Quantity->new($self->value);
  197:         }
  198:         when (OPERATOR) {
  199:             my @children = @{$self->children};
  200:             my ($q1, $q2);
  201:             if (defined $children[0]) {
  202:                 $q1 = $children[0]->calc($env);
  203:             }
  204:             if (defined $children[1]) {
  205:                 $q2 = $children[1]->calc($env);
  206:             }
  207:             given ($self->value) {
  208:                 when ("+") {
  209:                     if (!overload::Method($q1, '+')) {
  210:                         die CalcException->new("The [_1] operator is not implemented for this type.", $self->value);
  211:                     }
  212:                     return($q1 + $q2);
  213:                 }
  214:                 when ("-") {
  215:                     if (!defined $q2) {
  216:                         if (!$q1->can('qneg')) {
  217:                             die CalcException->new("Negation is not implemented for this type.");
  218:                         }
  219:                         return($q1->qneg());
  220:                     } else {
  221:                         if (!overload::Method($q1, '-')) {
  222:                             die CalcException->new("The [_1] operator is not implemented for this type.", $self->value);
  223:                         }
  224:                         return($q1 - $q2);
  225:                     }
  226:                 }
  227:                 when ("*") {
  228:                     if (!overload::Method($q1, '*')) {
  229:                         die CalcException->new("The [_1] operator is not implemented for this type.", $self->value);
  230:                     }
  231:                     return($q1 * $q2);
  232:                 }
  233:                 when ("/") {
  234:                     if (!overload::Method($q1, '/')) {
  235:                         die CalcException->new("The [_1] operator is not implemented for this type.", $self->value);
  236:                     }
  237:                     return($q1 / $q2);
  238:                 }
  239:                 when ("^") {
  240:                     if (!overload::Method($q1, '^')) {
  241:                         die CalcException->new("The [_1] operator is not implemented for this type.", $self->value);
  242:                     }
  243:                     return($q1 ^ $q2);
  244:                 }
  245:                 when ("!") {
  246:                     if (!$q1->can('qfact')) {
  247:                         die CalcException->new("The [_1] operator is not implemented for this type.", $self->value);
  248:                     }
  249:                     return $q1->qfact();
  250:                 }
  251:                 when ("%") {
  252:                     if (!$q1->isa(Quantity) || !$q2->isa(Quantity)) {
  253:                         die CalcException->new("The [_1] operator is not implemented for this type.", $self->value);
  254:                     }
  255:                     return(($q1 / Quantity->new(100)) * $q2);
  256:                 }
  257:                 when (".") {
  258:                     # scalar product for vectors, multiplication for matrices
  259:                     if (!$q1->can('qdot')) {
  260:                         die CalcException->new("The [_1] operator is not implemented for this type.", $self->value);
  261:                     }
  262:                     return($q1->qdot($children[1]->calc($env)));
  263:                 }
  264:                 when ("`") {
  265:                     if (!overload::Method($q1, '*')) {
  266:                         die CalcException->new("The [_1] operator is not implemented for this type.", $self->value);
  267:                     }
  268:                     return($q1 * $q2);
  269:                 }
  270:                 when ("=") {
  271:                     if (!$q1->can('qeq')) {
  272:                         die CalcException->new("The [_1] operator is not implemented for this type.", $self->value);
  273:                     }
  274:                     return($q1->qeq($q2, $env->tolerance));
  275:                 }
  276:                 when ("<") {
  277:                     if (!overload::Method($q1, '<')) {
  278:                         die CalcException->new("The [_1] operator is not implemented for this type.", $self->value);
  279:                     }
  280:                     return($q1 < $q2);
  281:                 }
  282:                 when ("<=") {
  283:                     if (!overload::Method($q1, '<=')) {
  284:                         die CalcException->new("The [_1] operator is not implemented for this type.", $self->value);
  285:                     }
  286:                     return($q1 <= $q2);
  287:                 }
  288:                 when (">") {
  289:                     if (!overload::Method($q1, '>')) {
  290:                         die CalcException->new("The [_1] operator is not implemented for this type.", $self->value);
  291:                     }
  292:                     return($q1 > $q2);
  293:                 }
  294:                 when (">=") {
  295:                     if (!overload::Method($q1, '>=')) {
  296:                         die CalcException->new("The [_1] operator is not implemented for this type.", $self->value);
  297:                     }
  298:                     return($q1 >= $q2);
  299:                 }
  300:                 default {
  301:                     die CalcException->new("Unknown operator: [_1].", $self->value);
  302:                 }
  303:             }
  304:         }
  305:         when (FUNCTION) {
  306:             my @children = @{$self->children};
  307:             my $fname = $children[0]->value;
  308:             
  309:             if (!defined $children[1]) {
  310:                 die CalcException->new("Missing parameter for function [_1].", $fname);
  311:             }
  312:             my ($q1, $q2);
  313:             if (string_in_array(['pow', 'sqrt', 'abs', 'exp', 'ln', 'log', 'log10', 'factorial',
  314:                     'mod', 'sgn', 'ceil', 'floor', 'sin', 'cos', 'tan', 'asin', 'acos', 'atan',
  315:                     'atan2', 'sinh', 'cosh', 'tanh', 'asinh', 'acosh', 'atanh'], $fname)) {
  316:                 $q1 = $children[1]->calc($env);
  317:                 if (!$q1->isa(Quantity)) {
  318:                     die CalcException->new("The [_1] function is not implemented for this type.", $fname);
  319:                 }
  320:             }
  321:             if (string_in_array(['pow', 'mod', 'atan2'], $fname)) {
  322:                 if (!defined $children[2]) {
  323:                     die CalcException->new("Missing parameter for function [_1].", $fname);
  324:                 }
  325:                 $q2 = $children[2]->calc($env);
  326:                 if (!$q2->isa(Quantity)) {
  327:                     die CalcException->new("The [_1] function is not implemented for this type.", $fname);
  328:                 }
  329:             }
  330:             given ($fname) {
  331:                 when ("matrix") {    return $self->createVectorOrMatrix($env); }
  332:                 when ("pow") {       return $q1->qpow($q2); }
  333:                 when ("sqrt") {      return $q1->qsqrt(); }
  334:                 when ("abs") {       return $q1->qabs(); }
  335:                 when ("exp") {       return $q1->qexp(); }
  336:                 when ("ln") {        return $q1->qln(); }
  337:                 when ("log") {       return $q1->qln(); }
  338:                 when ("log10") {     return $q1->qlog10(); }
  339:                 when ("factorial") { return $q1->qfact(); }
  340:                 when ("mod") {       return $q1->qmod($q2); }
  341:                 when ("sgn") {       return $q1->qsgn(); }
  342:                 when ("ceil") {      return $q1->qceil(); }
  343:                 when ("floor") {     return $q1->qfloor(); }
  344:                 when ("sin") {       return $q1->qsin(); }
  345:                 when ("cos") {       return $q1->qcos(); }
  346:                 when ("tan") {       return $q1->qtan(); }
  347:                 when ("asin") {      return $q1->qasin(); }
  348:                 when ("acos") {      return $q1->qacos(); }
  349:                 when ("atan") {      return $q1->qatan(); }
  350:                 when ("atan2") {     return $q1->qatan2($q2); }
  351:                 when ("sinh") {      return $q1->qsinh(); }
  352:                 when ("cosh") {      return $q1->qcosh(); }
  353:                 when ("tanh") {      return $q1->qtanh(); }
  354:                 when ("asinh") {     return $q1->qasinh(); }
  355:                 when ("acosh") {     return $q1->qacosh(); }
  356:                 when ("atanh") {     return $q1->qatanh(); }
  357:                 when (["sum","product"]) {
  358:                     if ($env->unit_mode) {
  359:                         die CalcException->new("[_1] cannot work in unit mode.", $fname);
  360:                     }
  361:                     if (scalar(@children) != 5) {
  362:                         die CalcException->new("[_1] should have four parameters.", $fname);
  363:                     }
  364:                     my $var = "".$children[2]->value;
  365:                     if ($var !~ /^[a-zA-Z_][a-zA-Z_0-9]*$/) {
  366:                         die CalcException->new("[_1]: wrong variable name", $fname);
  367:                     }
  368:                     if ($var eq "i") {
  369:                         die CalcException->new("[_1]: please use another variable name, i is the imaginary number.", $fname);
  370:                     }
  371:                     my $initial = $env->getVariable($var);
  372:                     my $var_value_1 = $children[3]->value;
  373:                     my $var_value_2 = $children[4]->value;
  374:                     if ($var_value_1 !~ /^[0-9]+$/) {
  375:                         die CalcException->new("[_1]: the third parameter should be an integer", $fname);
  376:                     }
  377:                     if ($var_value_2 !~ /^[0-9]+$/) {
  378:                         die CalcException->new("[_1]: the fourth parameter should be an integer", $fname);
  379:                     }
  380:                     if ($var_value_1 > $var_value_2) {
  381:                         die CalcException->new("[_1]: are you trying to make me loop forever?", $fname);
  382:                     }
  383:                     my $result;
  384:                     for (my $var_value=$var_value_1; $var_value <= $var_value_2; $var_value++) {
  385:                         $env->setVariable($var, $var_value);
  386:                         my $nq = $children[1]->calc($env);
  387:                         if (!$nq->isa(Quantity) && !$nq->isa(QVector) && !$nq->isa(QMatrix)) {
  388:                             die CalcException->new("[_1]: wrong type for a calculated value", $fname);
  389:                         }
  390:                         if (!defined $result) {
  391:                             $result = $nq;
  392:                         } elsif ($fname eq "sum") {
  393:                             $result += $nq;
  394:                         } else {
  395:                             $result *= $nq;
  396:                         }
  397:                     }
  398:                     $env->setVariable($var, $initial);
  399:                     return $result;
  400:                 }
  401:                 when ("binomial") {
  402:                     if (scalar(@children) != 3) {
  403:                         die CalcException->new("[_1] should have two parameters.", $fname);
  404:                     }
  405:                     my $n = $children[1]->calc($env);
  406:                     my $p = $children[2]->calc($env);
  407:                     if (!$n->isa(Quantity) || !$p->isa(Quantity)) {
  408:                         die CalcException->new("Wrong parameter type for function [_1]", $fname);
  409:                     }
  410:                     return $n->qfact() / ($p->qfact() * ($n - $p)->qfact());
  411:                 }
  412:                 when (["union","intersection"]) {
  413:                     if (!defined $children[2]) {
  414:                         die CalcException->new("Missing parameter for function [_1].", $fname);
  415:                     }
  416:                     my $p1 = $children[1]->calc($env);
  417:                     my $p2 = $children[2]->calc($env);
  418:                     if (!$p1->isa(QSet) && !$p1->isa(QInterval) && !$p1->isa(QIntervalUnion)) {
  419:                         die CalcException->new("Wrong type for function [_1] (should be a set or interval).", $fname);
  420:                     }
  421:                     if ($fname eq "union") {
  422:                         return $p1->union($p2);
  423:                     } else {
  424:                         return $p1->intersection($p2);
  425:                     }
  426:                 }
  427:                 default {            die CalcException->new("Unknown function: [_1].",$fname); }
  428:             }
  429:         }
  430:         when (VECTOR) {
  431:             return $self->createVectorOrMatrix($env);
  432:         }
  433:         when (INTERVAL) {
  434:             my @children = @{$self->children};
  435:             if (scalar(@children) != 2) {
  436:                 die CalcException->new("Interval should have two parameters.");
  437:             }
  438:             my $qmin = $children[0]->calc($env);
  439:             my $qmax = $children[1]->calc($env);
  440:             my ($qminopen, $qmaxopen);
  441:             given ($self->interval_type) {
  442:                 when (OPEN_OPEN) { $qminopen = 1; $qmaxopen = 1; }
  443:                 when (OPEN_CLOSED) { $qminopen = 1; $qmaxopen = 0; }
  444:                 when (CLOSED_OPEN) { $qminopen = 0; $qmaxopen = 1; }
  445:                 when (CLOSED_CLOSED) { $qminopen = 0; $qmaxopen = 0; }
  446:             }
  447:             return QInterval->new($qmin, $qmax, $qminopen, $qmaxopen);
  448:         }
  449:         when (SET) {
  450:             my @t = ();
  451:             foreach my $child (@{$self->children}) {
  452:                 push(@t, $child->calc($env));
  453:             }
  454:             return QSet->new(\@t);
  455:         }
  456:         when (SUBSCRIPT) {
  457:             die CalcException->new("Subscript cannot be evaluated: [_1].", $self->value);
  458:         }
  459:     }
  460: }
  461: 
  462: ##
  463: # Returns the equation as a string with the Maxima syntax.
  464: # @returns {string}
  465: ##
  466: sub toMaxima {
  467:     my ( $self, $env ) = @_;
  468:     
  469:     given ($self->type) {
  470:         when (UNKNOWN) {
  471:             die CalcException->new("Unknown node type: [_1].", $self->value);
  472:         }
  473:         when (NAME) {
  474:             my $name = $self->value;
  475:             my $cst = $env->getConstant($name);
  476:             if (defined $cst) {
  477:                 return $cst;
  478:             }
  479:             return($name);
  480:         }
  481:         when (NUMBER) {
  482:             if ($self->value eq "i") {
  483:                 return "%i";
  484:             } else {
  485:                 return $self->value;
  486:             }
  487:         }
  488:         when (OPERATOR) {
  489:             my @children = @{$self->children};
  490:             given ($self->value) {
  491:                 when ("+") {
  492:                     if ($children[0]->type == SET && $children[1]->type == SET) {
  493:                         return("union(".$children[0]->toMaxima().", ".$children[1]->toMaxima().")");
  494:                     } else {
  495:                         return("(".$children[0]->toMaxima()."+".$children[1]->toMaxima().")");
  496:                     }
  497:                 }
  498:                 when ("-") {
  499:                     if (!defined $children[1]) {
  500:                         return("(-".$children[0]->toMaxima().")");
  501:                     } else {
  502:                         return("(".$children[0]->toMaxima()."-".$children[1]->toMaxima().")");
  503:                     }
  504:                 }
  505:                 when ("*") {
  506:                     return("(".$children[0]->toMaxima()."*".$children[1]->toMaxima().")");
  507:                 }
  508:                 when ("/") {
  509:                     return("(".$children[0]->toMaxima()."/".$children[1]->toMaxima().")");
  510:                 }
  511:                 when ("^") {
  512:                     return("(".$children[0]->toMaxima()."^".$children[1]->toMaxima().")");
  513:                 }
  514:                 when ("!") {
  515:                     return("factorial(".$children[0]->toMaxima().")");
  516:                 }
  517:                 when ("%") {
  518:                     return("((".$children[0]->toMaxima()."/100)*".$children[1]->toMaxima().")");
  519:                 }
  520:                 when (".") {
  521:                     # scalar product for vectors, multiplication for matrices
  522:                     return("(".$children[0]->toMaxima().".".$children[1]->toMaxima().")");
  523:                 }
  524:                 when ("`") {
  525:                     return("(".$children[0]->toMaxima()."`".$children[1]->toMaxima().")");
  526:                 }
  527:                 when ("=") {
  528:                     # NOTE: should we use is(...) to evaluate the expression ?
  529:                     return("(".$children[0]->toMaxima()."=".$children[1]->toMaxima().")");
  530:                 }
  531:                 when ("<") {
  532:                     return("(".$children[0]->toMaxima()."<".$children[1]->toMaxima().")");
  533:                 }
  534:                 when (">") {
  535:                     return("(".$children[0]->toMaxima().">".$children[1]->toMaxima().")");
  536:                 }
  537:                 when ("<=") {
  538:                     return("(".$children[0]->toMaxima()."<=".$children[1]->toMaxima().")");
  539:                 }
  540:                 when (">=") {
  541:                     return("(".$children[0]->toMaxima().">=".$children[1]->toMaxima().")");
  542:                 }
  543:                 default {
  544:                     die CalcException->new("Unknown operator: [_1].", $self->value);
  545:                 }
  546:             }
  547:         }
  548:         when (FUNCTION) {
  549:             my @children = @{$self->children};
  550:             my $fname = $children[0]->value;
  551:             
  552:             given ($fname) {
  553:                 when ("log10") {  return "log(".$children[1]->toMaxima().")/log(10)"; }
  554:                 when ("sgn") {    return "signum(".$children[1]->toMaxima().")"; }
  555:                 when ("ceil") {   return "ceiling(".$children[1]->toMaxima().")"; }
  556:                 default {
  557:                     my $s = $fname."(";
  558:                     for (my $i=1; $i<scalar(@children); $i++) {
  559:                         if ($i != 1) {
  560:                             $s .= ", ";
  561:                         }
  562:                         $s .= $children[$i]->toMaxima();
  563:                     }
  564:                     $s .= ")";
  565:                     return($s);
  566:                 }
  567:             }
  568:         }
  569:         when (VECTOR) {
  570:             my @children = @{$self->children};
  571:             my $s;
  572:             if ($children[0]->type == VECTOR) {
  573:                 $s = "matrix(";
  574:             } else {
  575:                 $s = "[";
  576:             }
  577:             for (my $i=0; $i<scalar(@children); $i++) {
  578:                 if ($i != 0) {
  579:                     $s .= ", ";
  580:                 }
  581:                 $s .= $children[$i]->toMaxima();
  582:             }
  583:             if ($children[0]->type == VECTOR) {
  584:                 $s .= ")";
  585:             } else {
  586:                 $s .= "]";
  587:             }
  588:             return($s);
  589:         }
  590:         when (INTERVAL) {
  591:             die CalcException->new("Maxima syntax: intervals are not implemented.");
  592:             # see http://ieeexplore.ieee.org/xpls/icp.jsp?arnumber=5959544
  593:             # "New Package in Maxima for Single-Valued Interval Computation on Real Numbers"
  594:         }
  595:         when (SET) {
  596:             my @children = @{$self->children};
  597:             my $s = "{";
  598:             for (my $i=0; $i<scalar(@children); $i++) {
  599:                 if ($i != 0) {
  600:                     $s .= ", ";
  601:                 }
  602:                 $s .= $children[$i]->toMaxima();
  603:             }
  604:             $s .= "}";
  605:             return($s);
  606:         }
  607:         when (SUBSCRIPT) {
  608:             my @children = @{$self->children};
  609:             return("(".$children[0]->toMaxima()."_".$children[1]->toMaxima().")");
  610:         }
  611:     }
  612: }
  613: 
  614: ##
  615: # Returns the equation as a string with the TeX syntax.
  616: # @returns {string}
  617: ##
  618: sub toTeX {
  619:     my ( $self ) = @_;
  620:     
  621:     given ($self->type) {
  622:         when (UNKNOWN) {
  623:             die CalcException->new("Unknown node type: [_1].", $self->value);
  624:         }
  625:         when (NAME) {
  626:             my $name = $self->value;
  627:             if ($name =~ /^([a-zA-Z]+)([0-9]+)$/) {
  628:                 return($1."_{".$2."}");
  629:             }
  630:             my @greek = (
  631:                 "alpha", "beta", "gamma", "delta", "epsilon", "zeta",
  632:                 "eta", "theta", "iota", "kappa", "lambda", "mu",
  633:                 "nu", "xi", "omicron", "pi", "rho", "sigma",
  634:                 "tau", "upsilon", "phi", "chi", "psi", "omega",
  635:                 "Alpha", "Beta", "Gamma", "Delta", "Epsilon", "Zeta",
  636:                 "Eta", "Theta", "Iota", "Kappa", "Lambda", "Mu",
  637:                 "Nu", "Xi", "Omicron", "Pi", "Rho", "Sigma",
  638:                 "Tau", "Upsilon", "Phi", "Chi", "Psi", "Omega",
  639:             );
  640:             if (string_in_array(\@greek, $name)) {
  641:                 return('\\'.$name);
  642:             } elsif ($name eq "hbar") {
  643:                 return("\\hbar");
  644:             } elsif ($name eq "inf") {
  645:                 return("\\infty");
  646:             } elsif ($name eq "minf") {
  647:                 return("-\\infty");
  648:             } else {
  649:                 return($name);
  650:             }
  651:         }
  652:         when (NUMBER) {
  653:             return $self->value;
  654:         }
  655:         when (OPERATOR) {
  656:             my @children = @{$self->children};
  657:             my $c0 = $children[0];
  658:             my $c1 = $children[1];
  659:             given ($self->value) {
  660:                 when ("+") {
  661:                     # should we add parenthesis ? We need to check if there is a '-' to the left of c1
  662:                     my $par = 0;
  663:                     my $first = $c1;
  664:                     while ($first->type == OPERATOR) {
  665:                         if ($first->value eq "-" && scalar(@{$first->children}) == 1) {
  666:                             $par = 1;
  667:                             last;
  668:                         } elsif ($first->value eq "+" || $first->value eq "-" || $first->value eq "*") {
  669:                             $first = $first->children->[0];
  670:                         } else {
  671:                             last;
  672:                         }
  673:                     }
  674:                     my $s = $c0->toTeX()." + ".$c1->toTeX();
  675:                     if ($par) {
  676:                         $s = "(".$s.")";
  677:                     }
  678:                     return $s;
  679:                 }
  680:                 when ("-") {
  681:                     if (!defined $c1) {
  682:                         return("-".$c0->toTeX());
  683:                     } else {
  684:                         my $s = $c0->toTeX()." - ";
  685:                         my $par = ($c1->type == OPERATOR &&
  686:                             ($c1->value eq "+" || $c1->value eq "-"));
  687:                         if ($par) {
  688:                             $s .= "(".$c1->toTeX().")";
  689:                         } else {
  690:                             $s .= $c1->toTeX();
  691:                         }
  692:                         return $s;
  693:                     }
  694:                 }
  695:                 when ("*") {
  696:                     my $par = ($c0->type == OPERATOR && ($c0->value eq "+" || $c0->value eq "-"));
  697:                     my $s = $c0->toTeX();
  698:                     if ($par) {
  699:                         $s = "(".$s.")";
  700:                     }
  701:                     # should the x operator be visible ? We need to check if there is a number to the left of c1
  702:                     my $firstinc1 = $c1;
  703:                     while ($firstinc1->type == OPERATOR) {
  704:                         $firstinc1 = $firstinc1->children->[0];
  705:                     }
  706:                     # ... and if it's an operation between vectors/matrices, the * operator should be displayed
  707:                     # (it is ambiguous otherwise)
  708:                     # note: this will not work if the matrix is calculated, for instance with 2[1;2]*[3;4]
  709:                     if ($c0->type == VECTOR && $c1->type == VECTOR) {
  710:                         $s .= " * ";
  711:                     } elsif ($firstinc1->type == NUMBER) {
  712:                         $s .= " \\times ";
  713:                     } else {
  714:                         $s .= " ";
  715:                     }
  716:                     $par = ($c1->type == OPERATOR && ($c1->value eq "+" || $c1->value eq "-"));
  717:                     if ($par) {
  718:                         $s .= "(".$c1->toTeX().")";
  719:                     } else {
  720:                         $s .= $c1->toTeX();
  721:                     }
  722:                     return $s;
  723:                 }
  724:                 when ("/") {
  725:                     # NOTE: cfrac would be better but tth does not handle it
  726:                     return("\\frac{".$c0->toTeX()."}{".$c1->toTeX()."}");
  727:                 }
  728:                 when ("^") {
  729:                     my $par;
  730:                     if ($c0->type == FUNCTION) {
  731:                         if ($c0->value eq "sqrt" || $c0->value eq "abs" || $c0->value eq "matrix" ||
  732:                                 $c0->value eq "diff") {
  733:                             $par = 0;
  734:                         } else {
  735:                             $par = 1;
  736:                         }
  737:                     } elsif ($c0->type == OPERATOR) {
  738:                         $par = 1;
  739:                     } else {
  740:                         $par = 0;
  741:                     }
  742:                     if ($par) {
  743:                         return("(".$c0->toTeX().")^{".$c1->toTeX()."}");
  744:                     } else {
  745:                         return($c0->toTeX()."^{".$c1->toTeX()."}");
  746:                     }
  747:                 }
  748:                 when ("!") {
  749:                     return($c0->toTeX()." !");
  750:                 }
  751:                 when ("%") {
  752:                     return($c0->toTeX()." \\% ".$c1->toTeX());
  753:                 }
  754:                 when (".") {
  755:                     # scalar product for vectors, multiplication for matrices
  756:                     my $par = ($c0->type == OPERATOR && ($c0->value eq "+" || $c0->value eq "-"));
  757:                     my $s = $c0->toTeX();
  758:                     if ($par) {
  759:                         $s = "(".$s.")";
  760:                     }
  761:                     $s .= " \\cdot ";
  762:                     $par = ($c1->type == OPERATOR && ($c1->value eq "+" || $c1->value eq "-"));
  763:                     if ($par) {
  764:                         $s .= "(".$c1->toTeX().")";
  765:                     } else {
  766:                         $s .= $c1->toTeX();
  767:                     }
  768:                     return $s;
  769:                 }
  770:                 when ("`") {
  771:                     return($c0->toTeX()." \\mathrm{".$c1->toTeX()."}");
  772:                 }
  773:                 when ("=") {
  774:                     return($c0->toTeX()." = ".$c1->toTeX());
  775:                 }
  776:                 when ("#") {
  777:                     return($c0->toTeX()." \\not ".$c1->toTeX());
  778:                 }
  779:                 when ("<") {
  780:                     return($c0->toTeX()." < ".$c1->toTeX());
  781:                 }
  782:                 when (">") {
  783:                     return($c0->toTeX()." > ".$c1->toTeX());
  784:                 }
  785:                 when ("<=") {
  786:                     return($c0->toTeX()." \\leq ".$c1->toTeX());
  787:                 }
  788:                 when (">=") {
  789:                     return($c0->toTeX()." \\geq ".$c1->toTeX());
  790:                 }
  791:                 default {
  792:                     die CalcException->new("Unknown operator: [_1].", $self->value);
  793:                 }
  794:             }
  795:         }
  796:         when (FUNCTION) {
  797:             my @children = @{$self->children};
  798:             my $fname = $children[0]->value;
  799:             my $c1 = $children[1];
  800:             my $c2 = $children[2];
  801:             my $c3 = $children[3];
  802:             my $c4 = $children[4];
  803:             
  804:             given ($fname) {
  805:                 when ("sqrt") {   return "\\sqrt{".$c1->toTeX()."}"; }
  806:                 when ("abs") {    return "|".$c1->toTeX()."|"; }
  807:                 when ("exp") {    return "\\mathrm{e}^{".$c1->toTeX()."}"; }
  808:                 when ("diff") {
  809:                     if (scalar(@children) == 3) {
  810:                         return "\\frac{d}{d".$c2->toTeX()."} ".$c1->toTeX();
  811:                     } else {
  812:                         return "\\frac{d^{".$c3->toTeX()."}}{d ".$c2->toTeX().
  813:                             "^{".$c3->toTeX()."}} ".$c1->toTeX();
  814:                     }
  815:                 }
  816:                 when ("integrate") {
  817:                     if (scalar(@children) == 3) {
  818:                         return "\\int ".$c1->toTeX()." \\ d ".$c2->toTeX();
  819:                     } else {
  820:                         return "\\int_{".$c3->toTeX()."}^{".$c4->toTeX()."} ".
  821:                             $c1->toTeX()." \\ d ".$c2->toTeX();
  822:                     }
  823:                 }
  824:                 when ("sum") {
  825:                     return "\\sum_{".$c2->toTeX()."=".$c3->toTeX().
  826:                         "}^{".$c4->toTeX()."} ".$c1->toTeX();
  827:                 }
  828:                 when ("product") {
  829:                     return "\\prod_{".$c2->toTeX()."=".$c3->toTeX().
  830:                         "}^{".$c4->toTeX()."} ".$c1->toTeX();
  831:                 }
  832:                 when ("limit") {
  833:                     if (scalar(@children) < 4) {
  834:                         return "\\lim ".$c1->toTeX();
  835:                     } elsif (scalar(@children) == 4) {
  836:                         return "\\lim_{".$c2->toTeX()." \\to ".$c3->toTeX().
  837:                         "}".$c1->toTeX();
  838:                     } else {
  839:                         return "\\lim_{".$c2->toTeX()." \\to ".$c3->toTeX().
  840:                         (($c4->value eq "plus") ? "+" : "-").
  841:                         "}".$c1->toTeX();
  842:                     }
  843:                 }
  844:                 when ("binomial") {
  845:                     return "\\binom{".$c1->toTeX()."}{".$c2->toTeX()."}";
  846:                 }
  847:                 when (["union","intersection"]) {
  848:                     if (!defined $children[2]) {
  849:                         die CalcException->new("Missing parameter for function [_1].", $fname);
  850:                     }
  851:                     if ($c1->type != SET && $c1->type != INTERVAL && $c1->type != FUNCTION) {
  852:                         die CalcException->new("Wrong type for function [_1] (should be a set or interval).", $fname);
  853:                     }
  854:                     if ($fname eq "union") {
  855:                         return $c1->toTeX().' \cup '.$c2->toTeX();
  856:                     } else {
  857:                         return $c1->toTeX().' \cap '.$c2->toTeX();
  858:                     }
  859:                 }
  860:                 when ("sin") {     return "\\sin ".$c1->toTeX(); }
  861:                 when ("cos") {     return "\\cos ".$c1->toTeX(); }
  862:                 when ("tan") {     return "\\tan ".$c1->toTeX(); }
  863:                 when ("asin") {    return "\\arcsin ".$c1->toTeX(); }
  864:                 when ("acos") {    return "\\arccos ".$c1->toTeX(); }
  865:                 when ("atan") {    return "\\arctan ".$c1->toTeX(); }
  866:                 when ("sinh") {    return "\\sinh ".$c1->toTeX(); }
  867:                 when ("cosh") {    return "\\cosh ".$c1->toTeX(); }
  868:                 when ("tanh") {    return "\\tanh ".$c1->toTeX(); }
  869:                 default {
  870:                     my $s = $fname."(";
  871:                     for (my $i=1; $i<scalar(@children); $i++) {
  872:                         if ($i != 1) {
  873:                             $s .= ", ";
  874:                         }
  875:                         $s .= $children[$i]->toTeX();
  876:                     }
  877:                     $s .= ")";
  878:                     return($s);
  879:                 }
  880:             }
  881:         }
  882:         when (VECTOR) {
  883:             my @children = @{$self->children};
  884:             # my $s = "\\begin{pmatrix}";
  885:             # NOTE: pmatrix would be easier, but tth does not recognize it
  886:             my $col;
  887:             if (scalar(@children) == 0) {
  888:                 $col = 0;
  889:             } elsif ($children[0]->type == VECTOR) {
  890:                 $col = scalar(@{$children[0]->children});
  891:             } else {
  892:                 $col = 1;
  893:             }
  894:             my $s = "\\left( \\begin{array}{".('c' x $col)."}";
  895:             for (my $i=0; $i<scalar(@children); $i++) {
  896:                 if ($i != 0) {
  897:                     $s .= " \\\\ ";
  898:                 }
  899:                 if ($children[0]->type == VECTOR) {
  900:                     # matrix
  901:                     for (my $j=0; $j<scalar(@{$children[$i]->children}); $j++) {
  902:                         if ($j != 0) {
  903:                             $s .= " & ";
  904:                         }
  905:                         $s .= $children[$i]->children->[$j]->toTeX();
  906:                     }
  907:                 } else {
  908:                     # vector
  909:                     $s .= $children[$i]->toTeX();
  910:                 }
  911:             }
  912:             # $s .= "\\end{pmatrix}";
  913:             $s .= "\\end{array} \\right)";
  914:             return($s);
  915:         }
  916:         when (INTERVAL) {
  917:             my @children = @{$self->children};
  918:             if (scalar(@children) != 2) {
  919:                 die CalcException->new("Interval should have two parameters.");
  920:             }
  921:             my ($qminopen, $qmaxopen);
  922:             given ($self->interval_type) {
  923:                 when (OPEN_OPEN) { $qminopen = 1; $qmaxopen = 1; }
  924:                 when (OPEN_CLOSED) { $qminopen = 1; $qmaxopen = 0; }
  925:                 when (CLOSED_OPEN) { $qminopen = 0; $qmaxopen = 1; }
  926:                 when (CLOSED_CLOSED) { $qminopen = 0; $qmaxopen = 0; }
  927:             }
  928:             my $s = "\\left";
  929:             if ($qminopen) {
  930:                 $s .= "(";
  931:             } else {
  932:                 $s .= "[";
  933:             }
  934:             $s .= $children[0]->toTeX();
  935:             $s .= ", ";
  936:             $s .= $children[1]->toTeX();
  937:             $s .= "\\right";
  938:             if ($qmaxopen) {
  939:                 $s .= ")";
  940:             } else {
  941:                 $s .= "]";
  942:             }
  943:             return($s);
  944:         }
  945:         when (SET) {
  946:             my @children = @{$self->children};
  947:             my $s = "\\left\\{ {";
  948:             for (my $i=0; $i<scalar(@children); $i++) {
  949:                 if ($i != 0) {
  950:                     $s .= ", ";
  951:                 }
  952:                 $s .= $children[$i]->toTeX();
  953:             }
  954:             $s .= "}\\right\\}";
  955:             return($s);
  956:         }
  957:         when (SUBSCRIPT) {
  958:             my @children = @{$self->children};
  959:             return($children[0]->toTeX()."_{".$children[1]->toTeX()."}");
  960:         }
  961:     }
  962: }
  963: ##
  964: # Creates a vector or a matrix with this node
  965: # @param {CalcEnv} env - Calculation environment.
  966: # @returns {QVector|QMatrix}
  967: ##
  968: sub createVectorOrMatrix {
  969:     my ( $self, $env ) = @_;
  970:     my @children = @{$self->children};
  971:     my @t = (); # 1d or 2d array of Quantity
  972:     my $start;
  973:     if ($self->type == FUNCTION) {
  974:         $start = 1;
  975:     } else {
  976:         $start = 0;
  977:     }
  978:     my $nb1;
  979:     for (my $i=0; $i < scalar(@children) - $start; $i++) {
  980:         my $qv = $children[$i+$start]->calc($env);
  981:         my $nb2;
  982:         if ($qv->isa(Quantity)) {
  983:             $nb2 = 1;
  984:         } else {
  985:             $nb2 = scalar(@{$qv->quantities});
  986:         }
  987:         if (!defined $nb1) {
  988:             $nb1 = $nb2;
  989:         } elsif ($nb2 != $nb1) {
  990:             die CalcException->new("Inconsistent number of elements in a matrix.");
  991:         }
  992:         if ($qv->isa(Quantity)) {
  993:             $t[$i] = $qv;
  994:         } else {
  995:             $t[$i] = [];
  996:             for (my $j=0; $j < scalar(@{$qv->quantities}); $j++) {
  997:                 $t[$i][$j] = $qv->quantities->[$j];
  998:             }
  999:         }
 1000:     }
 1001:     if (ref($t[0]) eq 'ARRAY') {
 1002:         return QMatrix->new(\@t);
 1003:     } else {
 1004:         return QVector->new(\@t);
 1005:     }
 1006: }
 1007: 
 1008: ##
 1009: # Tests if a string is in an array (using eq) (to avoid using $value ~~ @array)
 1010: # @param {Array<string>} array - reference to the array of strings
 1011: # @param {string} value - the string to look for
 1012: # @returns 1 if found, 0 otherwise
 1013: ##
 1014: sub string_in_array {
 1015:   my ($array, $value) = @_;
 1016:   foreach my $v (@{$array}) {
 1017:     if ($v eq $value) {
 1018:       return 1;
 1019:     }
 1020:   }
 1021:   return 0;
 1022: }
 1023: 
 1024: 1;
 1025: __END__

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