#include "Config.hh"
#include "Symbols.hh"
#include "DisplayTeX.hh"
#include "Algorithm.hh"
#include "algorithms/substitute.hh"
#include "properties/LaTeXForm.hh"
#include "properties/Derivative.hh"
#include "properties/Accent.hh"
#include "properties/Tableau.hh"
#include "properties/FilledTableau.hh"
#include "properties/TableauInherit.hh"

#define nbsp   " "
//(( parent.utf8_output?(unichar(0x00a0)):" "))
#define zwnbsp ""
//(( parent.utf8_output?(unichar(0xfeff)):""))

using namespace cadabra;

#ifdef ENABLE_JUPYTER
const std::string discr = "";
#else
const std::string discr = "\\discretionary{}{}{}";
#endif

DisplayTeX::DisplayTeX(const Kernel& k, const Ex& e)
	: DisplayBase(k, e)
	{
	symmap = {
			{"\\hat", "\\widehat"},
			{"\\tilde", "\\widetilde"}
		};

	curly_bracket_operators = {
		"\\sqrt",
		"\\dot"
		};
	}

bool DisplayTeX::needs_brackets(Ex::iterator it)
	{
	// FIXME: may need looking at properties
	// FIXME: write as individual parent/current tests
	if(tree.is_head(it)) return false;

	std::string parent=*tree.parent(it)->name;
	std::string child =*it->name;

	if(parent=="\\partial" && (child=="\\sum" || child=="\\oplus")) return false; // Always handled by the functional argument. Was: true;

	if(parent=="\\int" && (child=="\\sum" || child=="\\oplus")) return true;

	if(parent=="\\indexbracket" && child=="\\prod") return false;

	const Derivative *der=kernel.properties.get<Derivative>(it);

	if(parent=="\\pow") {
		Ex::sibling_iterator sib=it;
		++sib;
		if(tree.index(it)==0 && *sib->name=="1" && *sib->multiplier==multiplier_t(1)/2) return false; // \sqrt{this}
		if(tree.index(it)==0 && !it->is_integer() && *it->multiplier!=1) return true;
		int nc = Ex::number_of_children(it);
		int ic = Algorithm::number_of_direct_indices(it);
		if(nc-ic>0) {
			Ex::sibling_iterator ch = Ex::begin(it);
			while(ch->is_index())
				++ch;
			bool rao = reads_as_operator(it, ch);
			if(rao)
				return true;
			}
		}

	if(parent=="\\oplus" && child=="\\otimes") return true;

	if(parent=="\\pow" && (child=="\\prod" || child=="\\sum" || child=="\\oplus" || der)) return  true;

	if(parent=="\\wedge" && child=="\\prod") return true;
	
	if(parent=="\\prod" || parent=="\\frac" || parent=="\\pow" || parent=="\\wedge") {
		if(*tree.parent(it)->name!="\\frac" && (*it->name=="\\sum" || *it->name=="\\oplus")) return true;
		//		if(*tree.parent(it)->name=="\\pow" && (*it->multiplier<0 || (*it->multiplier!=1 && *it->name!="1")) ) return true;
		}
	else if(it->fl.parent_rel==str_node::p_none) {   // function argument
		if(*it->name=="\\sum" || *it->name=="\\oplus" || *it->name=="\\pow") return false;
		}
	else {
		if(*it->name=="\\sum")  return true;
		if(*it->name=="\\oplus")  return true;
		if(*it->name=="\\prod") return true;
		}
	return false;
	}

bool DisplayTeX::reads_as_operator(Ex::iterator obj, Ex::iterator arg) const
	{
	const Derivative *der=kernel.properties.get<Derivative>(obj);
	if(der) {
		if(*arg->name=="\\pow") return true;
		// FIXME: this needs fine-tuning; there are more cases where
		// no brackets are needed.
		const LaTeXForm *lf = kernel.properties.get<LaTeXForm>(arg);
		if((*arg->name).size()==1 || lf || cadabra::symbols::greek.find(*arg->name)!=cadabra::symbols::greek.end()) return true;
		}

	if(*obj->name=="\\cos" || *obj->name=="\\sin" || *obj->name=="\\tan" || *obj->name=="\\exp") {
		const LaTeXForm *lf = kernel.properties.get<LaTeXForm>(arg);
		if(*arg->multiplier==1)
			if((*arg->name).size()==1 || lf || cadabra::symbols::greek.find(*arg->name)!=cadabra::symbols::greek.end()) return true;
		}

	auto it=curly_bracket_operators.find(*obj->name);
	if(it!=curly_bracket_operators.end()) return true;

	return false;
	}

void DisplayTeX::print_other(std::ostream& str, Ex::iterator it)
	{
	if(needs_brackets(it))
		str << "\\left(";

	// print multiplier and object name
	if(*it->multiplier!=1)
		print_multiplier(str, it);

	if(*it->name=="1") {
		if(*it->multiplier==1 || (*it->multiplier==-1)) // this would print nothing altogether.
			str << "1";
		if(needs_brackets(it))
			str << "\\right)";
		return;
		}

	Ex_comparator comp(kernel.properties);
	int num;
	auto prop=kernel.properties.get_with_pattern_ext<LaTeXForm>(it, comp, num, "", false, true);  // get property, ignore parent rel!
	const LaTeXForm *lf=prop.first;
	bool needs_extra_brackets=false;
	const Accent *ac=kernel.properties.get<Accent>(it);
	if(!ac && extra_brackets_for_symbols) { // accents should never get additional curly brackets, {\bar}{g} does not print.
		Ex::sibling_iterator sib=tree.begin(it);
		while(sib!=tree.end(it)) {
			if(sib->is_index())
				needs_extra_brackets=true;
			++sib;
			}
		}

	if(needs_extra_brackets) str << "{"; // to prevent double sup/sub script errors
	if(lf) {
		// Use the pattern as the lhs, and one-by-one the elements in
		// latex as the rhs. So
		//
		//     ket(A??) -> "|"
		//     ket(A??) -> A??
		//     ...
		// Then apply this to the original expression to be printed, e.g. ket(1).

		for(auto lt: lf->latex) {
			auto s = *(lt.begin()->name);
			if(s[0]=='\"') {
				s=s.substr(1,s.size()-2);
				str << s;
				if(lf->latex.size()==1)
					print_children(str, it);
				}
			else {
				Ex replacement("\\arrow");
				replacement.append_child(replacement.begin(), prop.second->obj.begin());
				replacement.append_child(replacement.begin(), lt.begin());
				Ex tmp(it);
				// The overall multiplier has already been printed, so set to one now.
				one(tmp.begin()->multiplier);
				substitute subs(kernel, tmp, replacement);
				auto lti=tmp.begin();
				if(subs.can_apply(lti))
					subs.apply(lti);
				// std::cerr << tmp << std::endl;
				dispatch(str, tmp.begin());
				}
			}
		}
	else {
		str << texify(*it->name);
		print_children(str, it);
		}

	if(needs_extra_brackets)
		str << "}";

	if(needs_brackets(it))
		str << "\\right)";
	}

void DisplayTeX::print_tableau(std::ostream& str, Ex::iterator it)
	{
	if(needs_brackets(it))
		str << "\\left(";

	// print multiplier and object name
	if(*it->multiplier!=1) {
		print_multiplier(str, it);
		str << "\\, ";
		}

	str << "\\ydiagram{";
	auto sib=tree.begin(it);
	while(sib!=tree.end(it)) {
		str << *sib->multiplier;
		++sib;
		if(sib!=tree.end(it))
			str << ",";
		}
	str << "}";
	
	if(needs_brackets(it))
		str << "\\right)";
	}

void DisplayTeX::print_ftableau(std::ostream& str, Ex::iterator it)
	{
	if(needs_brackets(it))
		str << "\\left(";

	// print multiplier and object name
	if(*it->multiplier!=1) {
		print_multiplier(str, it);
		str << "\\, ";
		}

	str << "\\ytableaushort{";
	auto sib=tree.begin(it);
	while(sib!=tree.end(it)) {
		if(*sib->name!="\\comma") {
			str << "{";
			dispatch(str, sib);
			str << "}";
			}
		else {
			auto sib2=tree.begin(sib);
			while(sib2!=tree.end(sib)) {
				str << "{";
				dispatch(str, sib2);
				str << "}";
				++sib2;
				}
			}
		++sib;
		if(sib!=tree.end(it))
			str << ",";
		}
	str << "}";

	if(needs_brackets(it))
		str << "\\right)";
	}

std::string DisplayTeX::texify(std::string str) const
	{
	auto rn = symmap.find(str);
	if(rn!=symmap.end())
		str = rn->second;

	// Convert symbols which need to be escaped for TeX.
	std::string res;
	for(unsigned int i=0; i<str.size(); ++i) {
		if(str[i]=='#') res+="\\#";
		else res+=str[i];
		}

	// Make symbols like "a13" print as "a_{13}" automatically.
	if(res.size()>1) {
		std::string nondigit;
		std::string digit;
		bool nd=true;
		for(size_t i=0; i<str.size(); ++i) {
			if(nd) {
				if(isdigit(str[i])) {
					nd=false;
					digit+=str[i];
					}
				else nondigit+=str[i];
				}
			else {
				if(isdigit(str[i])==false) {
					digit="";
					break; // nothing we can do here
					}
				else digit+=str[i];
				}
			}
		if(digit.size()>0 && nondigit.size()>0)
			res="{"+nondigit+"_{"+digit+"}}";
		}
	
	return res;
	}

void DisplayTeX::print_children(std::ostream& str, Ex::iterator it, int skip)
	{
	str_node::bracket_t    previous_bracket_   =str_node::b_invalid;
	str_node::parent_rel_t previous_parent_rel_=str_node::p_none;

	int number_of_nonindex_children=0;
	int number_of_index_children=0;
	Ex::sibling_iterator ch=tree.begin(it);
	while(ch!=tree.end(it)) {
		if(ch->is_index()==false) {
			++number_of_nonindex_children;
			if(*ch->name=="\\prod")
				++number_of_nonindex_children;
			}
		else ++number_of_index_children;
		++ch;
		}

	ch=tree.begin(it);
	ch+=skip;
	unsigned int chnum=0;
	while(ch!=tree.end(it)) {
		str_node::bracket_t    current_bracket_   =(*ch).fl.bracket;
		str_node::parent_rel_t current_parent_rel_=(*ch).fl.parent_rel;
		const Accent *is_accent=kernel.properties.get<Accent>(it);

		bool function_bracket_needed=true;
		if(current_bracket_==str_node::b_none) {
			if(previous_bracket_==str_node::b_none && current_parent_rel_==previous_parent_rel_ && current_parent_rel_==str_node::p_none)
				str << ", " << discr;
			function_bracket_needed=!reads_as_operator(it, ch);
			}

		if(current_bracket_!=str_node::b_none || previous_bracket_!=current_bracket_ || previous_parent_rel_!=current_parent_rel_) {
			print_parent_rel(str, current_parent_rel_, ch==tree.begin(it));

			if(is_accent==0 && function_bracket_needed)
				print_opening_bracket(str, (number_of_nonindex_children>1 /* &&number_of_index_children>0 */ &&
				                            current_parent_rel_!=str_node::p_sub &&
				                            current_parent_rel_!=str_node::p_super ? str_node::b_round:current_bracket_),
				                      current_parent_rel_);
			else str << "{";
			}

		// print this child depending on its name or meaning
		dispatch(str, ch);

		++ch;
		if(ch==tree.end(it) || current_bracket_!=str_node::b_none || current_bracket_!=(*ch).fl.bracket || current_parent_rel_!=(*ch).fl.parent_rel) {
			if(is_accent==0 && function_bracket_needed)
				print_closing_bracket(str,  (number_of_nonindex_children>1 /* &&number_of_index_children>0 */ &&
				                             current_parent_rel_!=str_node::p_sub &&
				                             current_parent_rel_!=str_node::p_super ? str_node::b_round:current_bracket_),
				                      current_parent_rel_);
			else str  << "}";
			}
		else str << nbsp;

		previous_bracket_=current_bracket_;
		previous_parent_rel_=current_parent_rel_;
		++chnum;
		}
	}

void DisplayTeX::print_multiplier(std::ostream& str, Ex::iterator it, int mult)
	{
	mpz_class denom=it->multiplier->get_den();

	if(denom!=1) {
		if(mult*it->multiplier->get_num()<0) {
			str << " - ";
			mult *= -1;
			}
		str << "\\frac{" << mult * it->multiplier->get_num() << "}{" << it->multiplier->get_den() << "}";
		}
	else if(mult * (*it->multiplier)==-1) {
		str << "-";
		}
	else {
		str << mult * (*it->multiplier);
		}
	}

void DisplayTeX::print_opening_bracket(std::ostream& str, str_node::bracket_t br, str_node::parent_rel_t pr)
	{
	switch(br) {
		case str_node::b_none:
			if(pr==str_node::p_none)     str << "\\left(";
			else                         str << "{";
			break;
		case str_node::b_pointy:
			str << "\\<";
			break;
		case str_node::b_curly:
			str << "\\left\\{";
			break;
		case str_node::b_round:
			str << "\\left(";
			break;
		case str_node::b_square:
			str << "\\left[";
			break;
		default :
			return;
		}
	++(bracket_level);
	}

void DisplayTeX::print_closing_bracket(std::ostream& str, str_node::bracket_t br, str_node::parent_rel_t pr)
	{
	switch(br) {
		case str_node::b_none:
			if(pr==str_node::p_none)     str << "\\right)";
			else                         str << "}";
			break;
		case str_node::b_pointy:
			str << "\\>";
			break;
		case str_node::b_curly:
			str << "\\right\\}";
			break;
		case str_node::b_round:
			str << "\\right)";
			break;
		case str_node::b_square:
			str << "\\right]";
			break;
		default :
			return;
		}
	--(bracket_level);
	}

void DisplayTeX::print_parent_rel(std::ostream& str, str_node::parent_rel_t pr, bool first)
	{
	switch(pr) {
		case str_node::p_super:
			if(!first && latex_spacing) str << "\\,";
			str << "^";
			break;
		case str_node::p_sub:
			if(!first && latex_spacing) str << "\\,";
			str << "_";
			break;
		case str_node::p_property:
			str << "$";
			break;
		case str_node::p_exponent:
			str << "**";
			break;
		case str_node::p_none:
			break;
		case str_node::p_components:
			break;
		case str_node::p_invalid:
			throw std::logic_error("DisplayTeX: p_invalid not handled.");
		}
	// Prevent line break after this character.
	str << zwnbsp;
	}

void DisplayTeX::dispatch(std::ostream& str, Ex::iterator it)
	{
	if(*it->name=="\\prod")                                   print_productlike(str, it, " ");
	else if(*it->name=="\\sum" || *it->name=="\\oplus")       print_sumlike(str, it);
	else if(*it->name=="\\frac")                              print_fraclike(str, it);
	else if(*it->name=="\\comma")                             print_commalike(str, it);
	else if(*it->name=="\\arrow")                             print_arrowlike(str, it);
	else if(*it->name=="\\inner")                             print_dot(str, it);
	else if(*it->name=="\\pow")                               print_powlike(str, it);
	else if(*it->name=="\\int")                               print_intlike(str, it);
	else if(*it->name=="\\equals" || *it->name=="\\unequals") print_equalitylike(str, it);
	else if(*it->name=="\\commutator")                        print_commutator(str, it, true);
	else if(*it->name=="\\anticommutator")                    print_commutator(str, it, false);
	else if(*it->name=="\\components")                        print_components(str, it);
	else if(*it->name=="\\wedge")                             print_wedgeproduct(str, it);
	else if(*it->name=="\\conditional")                       print_conditional(str, it);
	else if(*it->name=="\\greater" || *it->name=="\\less")    print_relation(str, it);
	else if(*it->name=="\\indexbracket")                      print_indexbracket(str, it);
	else if(*it->name=="\\ldots")                             print_dots(str, it);
	else if(kernel.properties.get<Tableau>(it))               print_tableau(str, it);
	else if(kernel.properties.get<FilledTableau>(it))         print_ftableau(str, it);
	else                                                      print_other(str, it);
	}

void DisplayTeX::print_commalike(std::ostream& str, Ex::iterator it)
	{
	Ex::sibling_iterator sib=tree.begin(it);
	bool first=true;
	str << "\\left[";
	while(sib!=tree.end(it)) {
		if(first)
			first=false;
		else
			str << ",~" << discr << " ";
		dispatch(str, sib);
		++sib;
		}
	str << "\\right]";
	}

void DisplayTeX::print_wedgeproduct(std::ostream& str, Ex::iterator it)
	{
	if(*it->multiplier!=1) {
		print_multiplier(str, it);
		}

	if(needs_brackets(it))
		str << "\\left(";

	Ex::sibling_iterator sib=tree.begin(it);
	dispatch(str, sib);
	++sib;
	while(sib!=tree.end(it)) {
		str << "\\wedge ";
		dispatch(str, sib);
		++sib;
		}

	if(needs_brackets(it))
		str << "\\right)";
	}

void DisplayTeX::print_arrowlike(std::ostream& str, Ex::iterator it)
	{
	Ex::sibling_iterator sib=tree.begin(it);
	dispatch(str, sib);
	str << " \\rightarrow ";
	++sib;
	dispatch(str, sib);
	}

void DisplayTeX::print_dot(std::ostream& str, Ex::iterator it)
	{
	Ex::sibling_iterator sib=tree.begin(it);
	dispatch(str, sib);
	str << " \\cdot ";
	++sib;
	dispatch(str, sib);
	}

void DisplayTeX::print_fraclike(std::ostream& str, Ex::iterator it)
	{
	Ex::sibling_iterator num=tree.begin(it), den=num;
	++den;

	int mult=1;
	if(*it->multiplier<0) {
		str << " - ";
		mult=-1;
		}
	str << "\\frac{";
	if(mult * (*it->multiplier)!=1) {
		print_multiplier(str, it, mult);
		}
	if(num->is_rational()==false || (mult * (*it->multiplier))==1)
		dispatch(str, num);
	str << "}{";
	dispatch(str, den);
	str << "}";
	}

void DisplayTeX::print_productlike(std::ostream& str, Ex::iterator it, const std::string& inbetween)
	{
	if(needs_brackets(it))
		str << "\\left(";

	if (kernel.display_fractions) {
		// If one (or more) of the factors is a negative power, split into top and
		// bottom parts and print as a fraction
		Ex pos("\\prod"), neg("\\prod");
		for (Ex::sibling_iterator beg = it.begin(), end = it.end(); beg != end; ++beg) {
			bool is_negexp = false;
			if (*beg->name == "\\pow") {
				Ex::sibling_iterator exponent = beg.begin();
				++exponent;
				if (*exponent->name == "1" && *exponent->multiplier < 0) {
					is_negexp = true;
					if (*exponent->multiplier == -1) {
						neg.append_child(neg.begin(), (Ex::iterator)beg.begin());
					}
					else {
						auto pos = neg.append_child(neg.begin(), (Ex::iterator)beg);
						exponent = pos.begin();
						++exponent;
						multiply(exponent->multiplier, -1);
					}
				}
			}
			if (!is_negexp) {
				pos.append_child(pos.begin(), (Ex::iterator)beg);
			}
		}

		if (neg.begin().begin() != neg.begin().end()) {
			auto mult = *it->multiplier;
			if (mult < 0) {
				str << "-";
				mult *= -1;
			}
			if (mult.get_den() == 1) {
				multiply(pos.begin()->multiplier, mult);
			}
			else {
				multiply(pos.begin()->multiplier, mult.get_num());
				multiply(neg.begin()->multiplier, mult.get_den());
			}
			str << "\\frac{";
			if (pos.begin().begin() == pos.begin().end()) {
				pos.begin()->name = name_set.insert("1").first;
				print_other(str, pos.begin());
			}
			else {
				print_productlike(str, pos.begin(), inbetween);
			}
			str << "}{";
			print_productlike(str, neg.begin(), inbetween);
			str << "}";

			if (needs_brackets(it))
				str << "\\right)";
			return;
		}
	}

	// The multiplier needs to be inside the brackets, otherwise things like
	// \pow{ 2/3 \prod{a}{b} }{c} do not print correctly.

	if(*it->multiplier!=1)
		print_multiplier(str, it);

	// To print \prod{\sum{a}{b}}{\sum{c}{d}} correctly:
	// If there is any sum as child, and if the sum children do not
	// all have the same bracket type (different from b_none or b_no),
	// then print brackets.

	str_node::bracket_t previous_bracket_=str_node::b_invalid;
//	bool beginning_of_group=true;
	Ex::sibling_iterator ch=tree.begin(it);
	bool prev_is_tableau=false;
	if(ch!=tree.end(it)) {
		const Tableau        *tab =kernel.properties.get<Tableau>(ch);
		const FilledTableau  *ftab=kernel.properties.get<FilledTableau>(ch);
		if(tab || ftab)
			prev_is_tableau=true;
		}
	while(ch!=tree.end(it)) {
		str_node::bracket_t current_bracket_=(*ch).fl.bracket;
		if(previous_bracket_!=current_bracket_) {
			if(current_bracket_!=str_node::b_none) {
				print_opening_bracket(str, current_bracket_, str_node::p_none);
//				beginning_of_group=true;
				}
			}
		dispatch(str, ch);
		++ch;
		if(ch==tree.end(it)) {
			if(current_bracket_!=str_node::b_none)
				print_closing_bracket(str, current_bracket_, str_node::p_none);
			}
		else {
			const Tableau       *tab =kernel.properties.get<Tableau>(ch);
			const FilledTableau *ftab=kernel.properties.get<FilledTableau>(ch);
			if(tab || ftab) {
				if(prev_is_tableau)
					str << " \\otimes ";
				else
					str << " ";
				prev_is_tableau=true;
				}
			else {
				prev_is_tableau=false;
				if(print_star) {
					if(tight_star) str << inbetween;
					else str << " " << inbetween << " ";
					}
				else {
					str << " ";
					}
				}
			}
		previous_bracket_=current_bracket_;
		}

	if(needs_brackets(it))
		str << "\\right)";

	}

void DisplayTeX::print_sumlike(std::ostream& str, Ex::iterator it)
	{
	assert(*it->multiplier==1);

	if(needs_brackets(it))
		str << "\\left(";

	unsigned int steps=0;

	Ex::sibling_iterator ch=tree.begin(it);
	bool prev_is_tableau=false;
	if(ch!=tree.end(it)) {
		const Tableau        *tab =kernel.properties.get<Tableau>(ch);
		const FilledTableau  *ftab=kernel.properties.get<FilledTableau>(ch);
		if(tab || ftab)
			prev_is_tableau=true;
		}
	while(ch!=tree.end(it)) {
		//		if(ch!=tree.begin(it))
		//			str << "%\n"; // prevent LaTeX overflow.
		if(++steps==20) {
			steps=0;
			str << "%\n"; // prevent LaTeX overflow.
			}
		if(*ch->multiplier>=0 && ch!=tree.begin(it)) {
			if(*it->name=="\\sum") {
				const Tableau       *tab =kernel.properties.get<Tableau>(ch);
				const FilledTableau *ftab=kernel.properties.get<FilledTableau>(ch);
				if(tab || ftab) {
					if(prev_is_tableau)
						str << " \\oplus ";
					else
						str << "+";
					prev_is_tableau=true;
					}
				else
					str << "+";
				}
			else
				str << *it->name << "{}";
			}

		dispatch(str, ch);
		++ch;
		}

	if(needs_brackets(it))
		str << "\\right)";
	str << std::flush;
	}

void DisplayTeX::print_powlike(std::ostream& str, Ex::iterator it)
	{
	auto arg=tree.begin(it);
	assert(arg!=tree.end(it));
	auto exp=arg;
	++exp;
	assert(exp!=tree.end(it));

	if (kernel.display_fractions && exp->is_rational() && *exp->multiplier < 0) {
		auto mult = *it->multiplier;
		bool mult_is_int = mult.get_den() == 1;
		if (mult < 0) {
			str << "-";
			mult *= -1;
		}
		str << "\\frac{";
		if (mult_is_int)
			str << mult;
		else
			str << mult.get_num();
		str << "}{";
		if (*exp->multiplier == -1) {
			Ex copy(arg);
			if (!mult_is_int)
				multiply(copy.begin()->multiplier, mult.get_den());
			dispatch(str, copy.begin());
		}
		else {
			Ex copy(it);
			exp = copy.begin().begin();
			++exp;
			multiply(exp->multiplier, -1);
			if (!mult_is_int)
				copy.begin()->multiplier = rat_set.insert(mult.get_den()).first;
			print_powlike(str, copy.begin());
		}
		str << "}";
		return;
	}

	if(*it->multiplier!=1)
		print_multiplier(str, it);

	bool is_sqrt=false;
	if(exp->is_rational() && *exp->multiplier==multiplier_t(1)/2) {
		str << "\\sqrt";
		is_sqrt=true;
		}

	str << "{";
	dispatch(str, arg);
	str << "}";

	if(!is_sqrt) {
		str << "^{";
		dispatch(str, exp);
		str << "}";
		}
	}

void DisplayTeX::print_intlike(std::ostream& str, Ex::iterator it)
	{
	if(*it->multiplier!=1)
		print_multiplier(str, it);
	str << *it->name;

	// The first argument is the integrand. Subsequent arguments are
	// either integration variables, or lists consisting of an
	// integration variable, a start value and an end value.
	// Since the integration ranges need to be attached to the
	// integral symbols, we need to scan for them first.

	auto sib=tree.begin(it);
	++sib;
	while(sib!=tree.end(it)) {
		if(*sib->name=="\\comma") {
			auto bvalue = tree.child(sib, 1);
			auto evalue = tree.child(sib, 2);
			str << "_{";
			dispatch(str, bvalue);
			str << "}^{";
			dispatch(str, evalue);
			str << "}";
			}
		++sib;
		if(sib!=tree.end(it))
			str << *it->name;
		}

	str << " ";
	sib=tree.begin(it);
	dispatch(str, sib);
	++sib;
	bool first=true;

	while(sib!=tree.end(it)) {
		if(first) {
			str << "\\,";
			first=false;
			}
		str << "\\,{\\rm d}";
		if(*sib->name=="\\comma") {
			dispatch(str, tree.child(sib,0));
			}
		else {
			dispatch(str, sib);
			}
		++sib;
		}
	}

void DisplayTeX::print_equalitylike(std::ostream& str, Ex::iterator it)
	{
	Ex::sibling_iterator sib=tree.begin(it);
	dispatch(str, sib);
	str << " ";
	if(*it->name=="\\unequals") str << "\\not";
	str << "= ";
	++sib;
	if(sib==tree.end(it))
		throw ConsistencyException("Found equals node with only one child node.");
	dispatch(str, sib);
	}

void DisplayTeX::print_commutator(std::ostream& str, Ex::iterator it, bool comm)
	{
	if(*it->multiplier!=1)
		print_multiplier(str, it);

	if(comm) str << "{}\\left[";
	else     str << "{}\\left\\{";
	auto sib=tree.begin(it);
	bool first=true;
	while(sib!=tree.end(it)) {
		if(!first) str << ", " << discr;
		else       first=false;
		dispatch(str, sib);
		++sib;
		}
	if(comm) str << "\\right]{}";
	else     str << "\\right\\}{}";
	}

void DisplayTeX::print_dots(std::ostream& str, Ex::iterator it)
	{
	if(tree.is_head(it)==false) {
		if(*tree.parent(it)->name=="\\sum")
			str << " \\ldots ";
		else
			str << " \\cdots ";
		}
	else
		str << " \\ldots ";
	}

void DisplayTeX::print_components(std::ostream& str, Ex::iterator it)
	{
	assert(*it->multiplier==1);

	auto ind_names=tree.begin(it);
	auto ind_values=tree.end(it);
	--ind_values;

	str << "\\square";
	auto sib=ind_names;
	while(sib!=ind_values) {
		if(sib->fl.parent_rel==str_node::p_sub)   str << "{}_{";
		if(sib->fl.parent_rel==str_node::p_super) str << "{}^{";
		dispatch(str, sib);
		str << "}";
		++sib;
		}

	str << "\\left\\{\\begin{aligned}";
	sib=tree.begin(ind_values);
	while(sib!=tree.end(ind_values)) {
		Ex::sibling_iterator c=tree.begin(sib);
		auto iv = tree.begin(c);
		auto in = ind_names;
		str << "\\square";
		while(iv!=tree.end(c)) {
			if(in->fl.parent_rel==str_node::p_sub)   str << "{}_{";
			if(in->fl.parent_rel==str_node::p_super) str << "{}^{";
			dispatch(str, iv);
			str << "}";
			++in;
			++iv;
			}
		str << "& = ";
		++c;
		dispatch(str, c);
		str << "\\\\[-.5ex]\n";
		++sib;
		}
	str << "\\end{aligned}\\right.\n";
	}

void DisplayTeX::print_conditional(std::ostream& str, Ex::iterator it)
	{
	auto sib=tree.begin(it);
	dispatch(str, sib);
	str << "\\quad\\text{with}\\quad{}";
	++sib;
	dispatch(str, sib);
	}

void DisplayTeX::print_relation(std::ostream& str, Ex::iterator it)
	{
	auto sib=tree.begin(it);
	dispatch(str, sib);
	if(*it->name=="\\greater") str << " > ";
	if(*it->name=="\\less")    str << " < ";
	++sib;
	dispatch(str, sib);
	}

void DisplayTeX::print_indexbracket(std::ostream& str, Ex::iterator it)
	{
	if(*it->multiplier!=1)
		print_multiplier(str, it);

	auto sib=tree.begin(it);
	str << "\\left(";
	dispatch(str, sib);
	str << "\\right)";
	print_children(str, it, 1);
	}

bool DisplayTeX::children_have_brackets(Ex::iterator ch) const
	{
	Ex::sibling_iterator chlds=tree.begin(ch);
	str_node::bracket_t childbr=chlds->fl.bracket;
	if(childbr==str_node::b_none || childbr==str_node::b_no)
		return false;
	else return true;
	}


// Thanks to Behdad Esfahbod
int k_unichar_to_utf8(kunichar c, char *buf)
	{
	buf[0]=(c) < 0x00000080 ?   (c)                  :
	       (c) < 0x00000800 ?  ((c) >>  6)         | 0xC0 :
	       (c) < 0x00010000 ?  ((c) >> 12)         | 0xE0 :
	       (c) < 0x00200000 ?  ((c) >> 18)         | 0xF0 :
	       (c) < 0x04000000 ?  ((c) >> 24)         | 0xF8 :
	       ((c) >> 30)         | 0xFC;

	buf[1]=(c) < 0x00000080 ?    0 /* null-terminator */     :
	       (c) < 0x00000800 ?  ((c)        & 0x3F) | 0x80 :
	       (c) < 0x00010000 ? (((c) >>  6) & 0x3F) | 0x80 :
	       (c) < 0x00200000 ? (((c) >> 12) & 0x3F) | 0x80 :
	       (c) < 0x04000000 ? (((c) >> 18) & 0x3F) | 0x80 :
	       (((c) >> 24) & 0x3F) | 0x80;

	buf[2]=(c) < 0x00000800 ?    0 /* null-terminator */     :
	       (c) < 0x00010000 ?  ((c)        & 0x3F) | 0x80 :
	       (c) < 0x00200000 ? (((c) >>  6) & 0x3F) | 0x80 :
	       (c) < 0x04000000 ? (((c) >> 12) & 0x3F) | 0x80 :
	       (((c) >> 18) & 0x3F) | 0x80;

	buf[3]=(c) < 0x00010000 ?    0 /* null-terminator */     :
	       (c) < 0x00200000 ?  ((c)        & 0x3F) | 0x80 :
	       (c) < 0x04000000 ? (((c) >>  6) & 0x3F) | 0x80 :
	       (((c) >> 12) & 0x3F) | 0x80;

	buf[4]=(c) < 0x00200000 ?    0 /* null-terminator */     :
	       (c) < 0x04000000 ?  ((c)        & 0x3F) | 0x80 :
	       (((c) >>  6) & 0x3F) | 0x80;

	buf[5]=(c) < 0x04000000 ?    0 /* null-terminator */     :
	       ((c)        & 0x3F) | 0x80;

	buf[6]=0;
	return 6;
	}

const char *unichar(kunichar c)
	{
	static char buffer[7];
	int pos=k_unichar_to_utf8(c, buffer);
	buffer[pos]=0;
	return buffer;
	}