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# The LearningOnline Network with CAPA - LON-CAPA
# Operator definitions
#
# $Id: Definitions.pm,v 1.2 2023/03/13 22:31:22 raeburn Exp $
#
# Copyright (C) 2014 Michigan State University Board of Trustees
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#

##
# Operator definitions (see function define() at the end).
##
package Apache::math_parser::Definitions;

use strict;
use warnings;
use utf8;

use JSON::DWIW;
use File::Slurp;

use aliased 'Apache::math_parser::ENode';
use aliased 'Apache::math_parser::Operator';
use aliased 'Apache::math_parser::ParseException';
use aliased 'Apache::math_parser::Parser';
use aliased 'Apache::math_parser::Token';

use constant ARG_SEPARATOR => ","; # ";" would be more international
use constant DECIMAL_SIGN_1 => ".";
use constant DECIMAL_SIGN_2 => "."; # with "," here
use constant INTERVAL_SEPARATOR => ":";

use vars qw(%perlvar);


##
# Constructor
##
sub new {
    my $class = shift;
    my $self = {
        _operators => [], # Array of Operator
    };
    bless $self, $class;
    return $self;
}

# Attribute helpers

##
# The operators.
# @returns {Operator[]}
##
sub operators {
    my $self = shift;
    return $self->{_operators};
}


##
# Creates a new operator.
# @param {string} id - Operator id (text used to recognize it)
# @param {integer} arity - Operator->UNARY, BINARY or TERNARY
# @param {integer} lbp - Left binding power
# @param {integer} rbp - Right binding power
# @param {function} nud - Null denotation function. Parameters: Operator, Parser. Returns: ENode.
# @param {function} led - Left denotation function. Parameters: Operator, Parser, ENode. Returns: ENode.
##
sub operator {
    my( $self, $id, $arity, $lbp, $rbp, $nud, $led ) = @_;
    push(@{$self->{_operators}}, Operator->new($id, $arity, $lbp, $rbp, $nud, $led));
}

##
# Creates a new separator operator.
# @param {string} id - Operator id (text used to recognize it)
##
sub separator {
    my( $self, $id ) = @_;
    $self->operator($id, Operator->BINARY, 0, 0);
}

##
# Creates a new infix operator.
# @param {string} id - Operator id (text used to recognize it)
# @param {integer} lbp - Left binding power
# @param {integer} rbp - Right binding power
# @optional {function} led - Left denotation function
##
sub infix {
    my( $self, $id, $lbp, $rbp, $led ) = @_;
    my $arity = Operator->BINARY;
    my $nud = undef;
    if (!defined $led) {
        $led = sub {
            my( $op, $p, $left ) = @_;
            my @children = ($left, $p->expression($rbp));
            return ENode->new(ENode->OPERATOR, $op, $id, \@children);
        }
    }
    $self->operator($id, $arity, $lbp, $rbp, $nud, $led);
}

##
# Creates a new prefix operator.
# @param {string} id - Operator id (text used to recognize it)
# @param {integer} rbp - Right binding power
# @optional {function} nud - Null denotation function
##
sub prefix {
    my( $self, $id, $rbp, $nud ) = @_;
    my $arity = Operator->UNARY;
    my $lbp = 0;
    if (!defined $nud) {
        $nud = sub {
            my( $op, $p ) = @_;
            my @children = ($p->expression($rbp));
            return ENode->new(ENode->OPERATOR, $op, $id, \@children);
        }
    }
    my $led = undef;
    $self->operator($id, $arity, $lbp, $rbp, $nud, $led);
}

##
# Creates a new suffix operator.
# @param {string} id - Operator id (text used to recognize it)
# @param {integer} lbp - Left binding power
# @optional {function} led - Left denotation function
##
sub suffix {
    my( $self, $id, $lbp, $led ) = @_;
    my $arity = Operator->UNARY;
    my $rbp = 0;
    my $nud = undef;
    if (!defined $led) {
        $led = sub {
            my( $op, $p, $left ) = @_;
            my @children = ($left);
            return ENode->new(ENode->OPERATOR, $op, $id, \@children);
        }
    }
    $self->operator($id, $arity, $lbp, $rbp, $nud, $led);
}

##
# Returns the defined operator with the given id
# @param {string} id - Operator id (text used to recognize it)
# @returns {Operator}
##
sub findOperator {
    my( $self, $id ) = @_;
    for (my $i=0; $i<scalar(@{$self->operators}); $i++) {
        if (@{$self->operators}[$i]->id eq $id) {
            return(@{$self->operators}[$i]);
        }
    }
    return undef;
}

##
# Led function for the ` (units) operator
# @param {Operator} op
# @param {Parser} p
# @param {ENode} left
# @returns {ENode}
##
sub unitsLed {
    my( $op, $p, $left ) = @_;
    # this led for units gathers all the units in an ENode
    my $right = $p->expression(125);
    while (defined $p->current_token && index("*/", $p->current_token->value) != -1) {
        my $token2 = $p->tokens->[$p->token_nr];
        if (!defined $token2) {
            last;
        }
        if ($token2->type != Token->NAME && $token2->value ne "(") {
            last;
        }
        my $token3 = $p->tokens->[$p->token_nr + 1];
        if (defined $token3 && ($token3->value eq "(" || $token3->type == Token->NUMBER)) {
            last;
        }
        # a check for constant names here is not needed because constant names are replaced in the tokenizer
        my $t = $p->current_token;
        $p->advance();
        $right = $t->op->led->($t->op, $p, $right);
    }
    my @children = ($left, $right);
    return ENode->new(ENode->OPERATOR, $op, $op->id, \@children);
}

##
# nud function for the ( operator (used to parse mathematical sub-expressions and intervals)
# @param {Operator} op
# @param {Parser} p
# @returns {ENode}
##
sub parenthesisNud {
    my( $op, $p ) = @_;
    my $e = $p->expression(0);
    if (defined $p->current_token && defined $p->current_token->op &&
            $p->current_token->op->id eq INTERVAL_SEPARATOR) {
        return buildInterval(0, $e, $op, $p);
    }
    $p->advance(")");
    return $e;
}

##
# Led function for the ( operator (used to parse function calls)
# @param {Operator} op
# @param {Parser} p
# @param {ENode} left
# @returns {ENode}
##
sub parenthesisLed {
    my( $op, $p, $left ) = @_;
    if ($left->type != ENode->NAME && $left->type != ENode->SUBSCRIPT) {
        die ParseException->new("Function name expected before a parenthesis.", $p->tokens->[$p->token_nr - 1]->from);
    }
    my @children = ($left);
    if ((!defined $p->current_token) || (!defined $p->current_token->op) || ($p->current_token->op->id ne ")")) {
        while (1) {
            push(@children, $p->expression(0));
            if (!defined $p->current_token || !defined $p->current_token->op || $p->current_token->op->id ne ARG_SEPARATOR) {
                last;
            }
            $p->advance(ARG_SEPARATOR);
        }
    }
    $p->advance(")");
    return ENode->new(ENode->FUNCTION, $op, $op->id, \@children);
}

##
# nud function for the [ operator (used to parse vectors and intervals)
# @param {Operator} op
# @param {Parser} p
# @returns {ENode}
##
sub squareBracketNud {
    my( $op, $p ) = @_;
    my @children = ();
    if (!defined $p->current_token || !defined $p->current_token->op || $p->current_token->op->id ne "]") {
        my $e = $p->expression(0);
        if (defined $p->current_token && defined $p->current_token->op &&
                $p->current_token->op->id eq INTERVAL_SEPARATOR) {
            return buildInterval(1, $e, $op, $p);
        }
        while (1) {
            push(@children, $e);
            if (!defined $p->current_token || !defined $p->current_token->op || $p->current_token->op->id ne ARG_SEPARATOR) {
                last;
            }
            $p->advance(ARG_SEPARATOR);
            $e = $p->expression(0);
        }
    }
    $p->advance("]");
    return ENode->new(ENode->VECTOR, $op, undef, \@children);
}

##
# Led function for the [ operator (used to parse subscript)
# @param {Operator} op
# @param {Parser} p
# @param {ENode} left
# @returns {ENode}
##
sub subscriptLed {
    my( $op, $p, $left ) = @_;
    if ($left->type != ENode->NAME && $left->type != ENode->SUBSCRIPT) {
        die ParseException->new("Name expected before a square bracket.", $p->tokens->[$p->token_nr - 1]->from);
    }
    my @children = ($left);
    if (!defined $p->current_token || !defined $p->current_token->op || $p->current_token->op->id != "]") {
        while (1) {
            push(@children, $p->expression(0));
            if (!defined $p->current_token || !defined $p->current_token->op || $p->current_token->op->id ne ARG_SEPARATOR) {
                last;
            }
            $p->advance(ARG_SEPARATOR);
        }
    }
    $p->advance("]");
    return ENode->new(ENode->SUBSCRIPT, $op, "[", \@children);
}

##
# Returns the ENode for the interval, parsing starting just before the interval separator
# @param {boolean} closed - was the first operator closed ?
# @param {ENode} e1 - First argument (already parsed)
# @param {Operator} op - The operator
# @param {Parser} p - The parser
# @returns {ENode}
##
sub buildInterval {
    my ($closed, $e1, $op, $p) = @_;
    $p->advance(INTERVAL_SEPARATOR);
    my $e2 = $p->expression(0);
    if (!defined $p->current_token || !defined $p->current_token->op ||
            ($p->current_token->op->id ne ")" && $p->current_token->op->id ne "]")) {
        die ParseException->new("Wrong interval syntax.", $p->tokens->[$p->token_nr - 1]->from);
    }
    my $interval_type;
    if ($p->current_token->op->id eq ")") {
        $p->advance(")");
        if ($closed) {
            $interval_type = ENode->CLOSED_OPEN;
        } else {
            $interval_type = ENode->OPEN_OPEN;
        }
    } else {
        $p->advance("]");
        if ($closed) {
            $interval_type = ENode->CLOSED_CLOSED;
        } else {
            $interval_type = ENode->OPEN_CLOSED;
        }
    }
    return ENode->new(ENode->INTERVAL, $op, undef, [$e1, $e2], $interval_type);
}

##
# nud function for the { operator (used to parse sets)
# @param {Operator} op
# @param {Parser} p
# @returns {ENode}
##
sub curlyBracketNud {
    my( $op, $p ) = @_;
    my @children = ();
    if (!defined $p->current_token || !defined $p->current_token->op || $p->current_token->op->id ne "}") {
        while (1) {
            push(@children, $p->expression(0));
            if (!defined $p->current_token || !defined $p->current_token->op || $p->current_token->op->id ne ARG_SEPARATOR) {
                last;
            }
            $p->advance(ARG_SEPARATOR);
        }
    }
    $p->advance("}");
    return ENode->new(ENode->SET, $op, undef, \@children);
}

##
# Defines all the operators.
##
sub define {
    my( $self ) = @_;
    $self->suffix("!", 160);
    $self->infix("^", 140, 139);
    $self->infix(".", 130, 129);
    $self->infix("`", 125, 125, \&unitsLed);
    $self->infix("*", 120, 120);
    $self->infix("/", 120, 120);
    $self->infix("%", 120, 120);
    $self->infix("+", 100, 100);
    $self->operator("-", Operator->BINARY, 100, 134, sub {
        my( $op, $p ) = @_;
        my @children = ($p->expression($op->rbp));
        return ENode->new(ENode->OPERATOR, $op, $op->id, \@children);
    }, sub {
        my( $op, $p, $left ) = @_;
        my @children = ($left, $p->expression(100));
        return ENode->new(ENode->OPERATOR, $op, $op->id, \@children);
    });
    $self->infix("=", 80, 80);
    $self->infix("#", 80, 80);
    $self->infix("<=", 80, 80);
    $self->infix(">=", 80, 80);
    $self->infix("<", 80, 80);
    $self->infix(">", 80, 80);
    
    $self->separator(")");
    $self->separator(ARG_SEPARATOR);
    $self->separator(INTERVAL_SEPARATOR);
    $self->operator("(", Operator->BINARY, 200, 200, \&parenthesisNud, \&parenthesisLed);
    
    $self->separator("]");
    $self->operator("[", Operator->BINARY, 200, 70, \&squareBracketNud, \&subscriptLed);
    
    $self->separator("}");
    $self->prefix("{", 200, \&curlyBracketNud);
}


1;
__END__