Fix translation of special characters in psql's LaTeX output modes.

tglsfdc · tglsfdc · commit 74bfb5388da8 · 2018-11-26T17:32:51.000-05:00
latex_escaped_print() mistranslated \ and failed to provide any translation for # ^ and ~, all of which would typically lead to LaTeX document syntax errors. In addition it didn't translate < > and |, which would typically render as unexpected characters. To some extent this represents shortcomings in ancient versions of LaTeX, which if memory serves had no easy way to render these control characters as ASCII text. But that's been fixed for, um, decades. In any case there is no value in emitting guaranteed-to-fail output for these characters. Noted while fooling with test cases added by commit 9a98984. Back-patch the code change to all supported versions.
diff --git a/src/bin/psql/print.c b/src/bin/psql/print.c
@@ -1579,28 +1579,52 @@ latex_escaped_print(const char *in, FILE *fout)
 	for (p = in; *p; p++)
 		switch (*p)
 		{
-			case '&':
-				fputs("\\&", fout);
+				/*
+				 * We convert ASCII characters per the recommendations in
+				 * Scott Pakin's "The Comprehensive LATEX Symbol List",
+				 * available from CTAN.  For non-ASCII, you're on your own.
+				 */
+			case '#':
+				fputs("\\#", fout);
+				break;
+			case '$':
+				fputs("\\$", fout);
 				break;
 			case '%':
 				fputs("\\%", fout);
 				break;
-			case '$':
-				fputs("\\$", fout);
+			case '&':
+				fputs("\\&", fout);
+				break;
+			case '<':
+				fputs("\\textless{}", fout);
+				break;
+			case '>':
+				fputs("\\textgreater{}", fout);
+				break;
+			case '\\':
+				fputs("\\textbackslash{}", fout);
+				break;
+			case '^':
+				fputs("\\^{}", fout);
 				break;
 			case '_':
 				fputs("\\_", fout);
 				break;
 			case '{':
 				fputs("\\{", fout);
 				break;
+			case '|':
+				fputs("\\textbar{}", fout);
+				break;
 			case '}':
 				fputs("\\}", fout);
 				break;
-			case '\\':
-				fputs("\\backslash", fout);
+			case '~':
+				fputs("\\~{}", fout);
 				break;
 			case '\n':
+				/* This is not right, but doing it right seems too hard */
 				fputs("\\\\", fout);
 				break;
 			default:
