Replace Greek letters entered as unicode instead of TeX

People doing quick and dirty things might want to create a new
expression by copying and pasting from the output of a previous
algorithm. The asymmetry here is that input typically has TeX while
output typically has unicode. We can solve this by performing a
replacement in the parser. It is then natural to copy greekmap from
DisplayTerminal to Symbols (and add varphi to it).

In case there are users who input both TeX and unicode and rely on them
being distinct, this could be put behind a command-line argument or
environment variable.

Signed-off-by: Connor Behan <[email protected]>

Author: cbehan

core/Parser.cc

@@ -20,6 +20,7 @@ You should have received a copy of the GNU General Public License
 
 #include "Parser.hh"
 #include "PreProcessor.hh"
+#include "Symbols.hh"
 
 #include <sstream>
 #include <internal/uniconv.h>
@@ -178,6 +179,17 @@ bool Parser::string2tree(const std::string& inp)
 	ss2 << pp;
 	std::string str8="  "+ss2.str()+"  "; // for lookahead
 
+#ifdef DEBUG
+	std::cout << "converting Greek unicode to TeX" << std::endl;
+#endif
+	for (auto const& c : cadabra::symbols::greekmap) {
+		size_t pos1 = 0;
+		size_t pos2;
+		while ((pos2 = str8.find(c.second, pos1)) != std::string::npos) {
+			str8.replace(pos2, c.second.length(), c.first);
+			pos1 = pos2 + c.first.length();
+			}
+		}
 #ifdef DEBUG
 	std::cout << "converting to utf32" << std::endl;
 #endif

core/Symbols.cc

@@ -54,3 +54,55 @@ const std::set<std::string> cadabra::symbols::greek {
 	"\\Omega"
 	};
 
+const std::map<std::string, std::string> cadabra::symbols::greekmap {
+	{"\\alpha",   "α" },
+	{"\\beta",    "β" },  // beta seems to be reserved
+	{"\\gamma",   "γ" }, // gamma seems to be reserved
+	{"\\delta",   "δ" },
+	{"\\epsilon", "ε" },
+	{"\\zeta",    "ζ" },
+	{"\\eta",     "η" },
+	{"\\theta",   "θ" },
+	{"\\iota",    "ι" },
+	{"\\kappa",   "κ" },
+	{"\\lambda",  "λ" }, // lambda is reserved
+	{"\\mu",      "μ" },
+	{"\\nu",      "ν" },
+	{"\\xi",      "ξ" },
+	{"\\omicron", "ο" },
+	{"\\pi",      "π" },
+	{"\\rho",     "ρ" },
+	{"\\sigma",   "σ" },
+	{"\\tau",     "τ" },
+	{"\\upsilon", "υ" },
+	{"\\phi",     "φ" },
+	{"\\varphi",  "ϕ" },
+	{"\\chi",     "χ" },
+	{"\\psi",     "ψ" },
+	{"\\omega",   "ω" },
+
+	{"\\Alpha",   "Α" },
+	{"\\Beta",    "Β" },
+	{"\\Gamma",   "Γ" },
+	{"\\Delta",   "Δ" },
+	{"\\Epsilon", "Ε" },
+	{"\\Zeta",    "Ζ" },
+	{"\\Eta",     "Η" },
+	{"\\Theta",   "ϴ" },
+	{"\\Iota",    "Ι" },
+	{"\\Kappa",   "Κ" },
+	{"\\Lambda",  "Λ" },
+	{"\\Mu",      "Μ" },
+	{"\\Nu",      "Ν" },
+	{"\\Xi",      "Ξ" },
+	{"\\Omicron", "Ο" },
+	{"\\Pi",      "Π" },
+	{"\\Rho",     "Ρ" },
+	{"\\Sigma",   "Σ" },
+	{"\\Tau",     "Τ" },
+	{"\\Upsilon", "Υ" },
+	{"\\Phi",     "Φ" },
+	{"\\Chi",     "Χ" },
+	{"\\Psi",     "Ψ" },
+	{"\\Omega",   "Ω" },
+	};

core/Symbols.hh

@@ -2,10 +2,12 @@
 #pragma once
 
 #include <set>
+#include <map>
 #include <string>
 
 namespace cadabra {
 	namespace symbols {
 		extern const std::set<std::string> greek;
+		extern const std::map<std::string, std::string> greekmap;
 		}
 	}