--- loncom/homework/math_parser/ENode.pm	2015/06/29 15:42:13	1.1
+++ loncom/homework/math_parser/ENode.pm	2017/01/27 20:24:26	1.5
@@ -26,7 +26,7 @@ use strict;
 use warnings;
 use utf8;
 
-use feature "switch"; # Perl 5.10.1
+use Switch 'Perl6';
 
 use aliased 'Apache::math_parser::CalcException';
 use aliased 'Apache::math_parser::Operator';
@@ -50,13 +50,16 @@ use enum qw(NOT_AN_INTERVAL OPEN_OPEN OP
 # @param {interval_type} - The interval type, NOT_AN_INTERVAL | OPEN_OPEN | OPEN_CLOSED | CLOSED_OPEN | CLOSED_CLOSED
 ##
 sub new {
-    my $class = shift;
+    my ($class, $type, $op, $value, $children, $interval_type) = @_;
+    if (!defined $interval_type) {
+        $interval_type = NOT_AN_INTERVAL;
+    }
     my $self = {
-        _type => shift,
-        _op => shift,
-        _value => shift,
-        _children => shift,
-        _interval_type => shift // NOT_AN_INTERVAL,
+        _type => $type,
+        _op => $op,
+        _value => $value,
+        _children => $children,
+        _interval_type => $interval_type,
     };
     bless $self, $class;
     return $self;
@@ -307,15 +310,15 @@ sub calc {
                 die CalcException->new("Missing parameter for function [_1].", $fname);
             }
             my ($q1, $q2);
-            if ($fname ~~ ['pow', 'sqrt', 'abs', 'exp', 'ln', 'log', 'log10', 'factorial',
+            if (string_in_array(['pow', 'sqrt', 'abs', 'exp', 'ln', 'log', 'log10', 'factorial',
                     'mod', 'sgn', 'ceil', 'floor', 'sin', 'cos', 'tan', 'asin', 'acos', 'atan',
-                    'atan2', 'sinh', 'cosh', 'tanh', 'asinh', 'acosh', 'atanh']) {
+                    'atan2', 'sinh', 'cosh', 'tanh', 'asinh', 'acosh', 'atanh'], $fname)) {
                 $q1 = $children[1]->calc($env);
                 if (!$q1->isa(Quantity)) {
                     die CalcException->new("The [_1] function is not implemented for this type.", $fname);
                 }
             }
-            if ($fname ~~ ['pow', 'mod', 'atan2']) {
+            if (string_in_array(['pow', 'mod', 'atan2'], $fname)) {
                 if (!defined $children[2]) {
                     die CalcException->new("Missing parameter for function [_1].", $fname);
                 }
@@ -634,7 +637,7 @@ sub toTeX {
                 "Nu", "Xi", "Omicron", "Pi", "Rho", "Sigma",
                 "Tau", "Upsilon", "Phi", "Chi", "Psi", "Omega",
             );
-            if ($name ~~ @greek) {
+            if (string_in_array(\@greek, $name)) {
                 return('\\'.$name);
             } elsif ($name eq "hbar") {
                 return("\\hbar");
@@ -743,7 +746,12 @@ sub toTeX {
                     }
                 }
                 when ("!") {
-                    return($c0->toTeX()." !");
+                    my $s = $c0->toTeX();
+                    if ($c0->type == OPERATOR) {
+                        $s = "(".$s.")";
+                    }
+                    $s .= " !";
+                    return $s;
                 }
                 when ("%") {
                     return($c0->toTeX()." \\% ".$c1->toTeX());
@@ -802,6 +810,14 @@ sub toTeX {
                 when ("sqrt") {   return "\\sqrt{".$c1->toTeX()."}"; }
                 when ("abs") {    return "|".$c1->toTeX()."|"; }
                 when ("exp") {    return "\\mathrm{e}^{".$c1->toTeX()."}"; }
+                when ("factorial") {
+                    my $s = $c1->toTeX();
+                    if ($c1->type == OPERATOR) {
+                        $s = "(".$s.")";
+                    }
+                    $s .= " !";
+                    return $s;
+                }
                 when ("diff") {
                     if (scalar(@children) == 3) {
                         return "\\frac{d}{d".$c2->toTeX()."} ".$c1->toTeX();
@@ -833,9 +849,14 @@ sub toTeX {
                         return "\\lim_{".$c2->toTeX()." \\to ".$c3->toTeX().
                         "}".$c1->toTeX();
                     } else {
-                        return "\\lim_{".$c2->toTeX()." \\to ".$c3->toTeX().
-                        (($c4->value eq "plus") ? "+" : "-").
-                        "}".$c1->toTeX();
+                        my $s = "\\lim_{".$c2->toTeX()." \\to ".$c3->toTeX();
+                        if ($c4->value eq "plus") {
+                            $s .= "+";
+                        } elsif ($c4->value eq "minus") {
+                            $s .= "-";
+                        }
+                        $s .= "}".$c1->toTeX();
+                        return $s;
                     }
                 }
                 when ("binomial") {
@@ -1002,5 +1023,21 @@ sub createVectorOrMatrix {
     }
 }
 
+##
+# Tests if a string is in an array (using eq) (to avoid using $value ~~ @array)
+# @param {Array<string>} array - reference to the array of strings
+# @param {string} value - the string to look for
+# @returns 1 if found, 0 otherwise
+##
+sub string_in_array {
+  my ($array, $value) = @_;
+  foreach my $v (@{$array}) {
+    if ($v eq $value) {
+      return 1;
+    }
+  }
+  return 0;
+}
+
 1;
 __END__