Improve automatic text quoting so it minimizes escape sequences when

possible.

stdlib/text.c

@@ -1027,7 +1027,7 @@ static inline Text_t _quoted(Text_t text, bool colorize, char quote_char)
         add_char('$');
     add_char(quote_char);
 
-#define add_escaped(str) ({ if (colorize) add_str("\x1b[34;1m"); add_char('\\'); add_str(str); if (colorize) add_str("\x1b[0;35m"); })
+#define add_escaped(str) ({ if (colorize) add_str("\x1b[34;1m"); add_str("$\\"); add_str(str); if (colorize) add_str("\x1b[0;35m"); })
     TextIter_t state = {text, 0, 0};
     for (int64_t i = 0; i < text.length; i++) {
         int32_t g = Text$get_grapheme_fast(&state, i);
@@ -1040,7 +1040,7 @@ static inline Text_t _quoted(Text_t text, bool colorize, char quote_char)
         case '\r': add_escaped("r"); break;
         case '\t': add_escaped("t"); break;
         case '\v': add_escaped("v"); break;
-        case '\\': add_escaped("\\"); break;
+        case '$': if (quote_char == '\'') add_char('$'); else add_escaped("$"); break;
         case '\x00' ... '\x06': case '\x0E' ... '\x1A':
         case '\x1C' ... '\x1F': case '\x7F' ... '\x7F': {
             if (colorize) add_str("\x1b[34;1m");
@@ -1082,7 +1082,43 @@ public Text_t Text$as_text(const void *text, bool colorize, const TypeInfo *info
     }
 
     if (!text) return info && info->TextInfo.lang ? Text$from_str(info->TextInfo.lang) : Text("Text");
-    Text_t as_text = _quoted(*(Text_t*)text, colorize, info == &Pattern$info ? '/' : '"');
+    char quote_char;
+    if (info == &Pattern$info) {
+        quote_char = '/';
+    } else {
+        // Figure out the best quotation mark to use:
+        bool has_dollar = false, has_double_quote = false, has_backtick = false,
+             has_single_quote = false, needs_escapes = false;
+        TextIter_t state = {*(Text_t*)text, 0, 0};
+        for (int64_t i = 0; i < state.text.length; i++) {
+            int32_t g = Text$get_grapheme_fast(&state, i);
+            if (g == '$') {
+                has_dollar = true;
+            } else if (g == '"') {
+                has_double_quote = true;
+            } else if (g == '`') {
+                has_backtick = true;
+            } else if (g == (g & 0x7F) && (g == '\'' || g == '\n' || g == '\r' || g == '\t' || !isprint((char)g))) {
+                needs_escapes = true;
+            }
+        }
+
+        // If there's dollar signs and/or double quotes in the string, it would
+        // be nice to avoid needing to escape them by using single quotes, but
+        // only if we don't have single quotes or need to escape anything else
+        // (because single quotes don't have interpolation):
+        if ((has_dollar || has_double_quote) && !has_single_quote && !needs_escapes)
+            quote_char = '\'';
+        // If there is a double quote, but no backtick, we can save a bit of
+        // escaping by using backtick instead of double quote:
+        else if (has_double_quote && !has_backtick)
+            quote_char = '`';
+        // Otherwise fall back to double quotes as the default quoting style:
+        else
+            quote_char = '"';
+    }
+
+    Text_t as_text = _quoted(*(Text_t*)text, colorize, quote_char);
     if (info && info->TextInfo.lang && info != &Text$info && info != &Pattern$info)
         as_text = Text$concat(
             colorize ? Text("\x1b[1m$") : Text("$"),

test/enums.tm

@@ -55,11 +55,11 @@ func main():
 	>> choose_text(Foo.Two(123, 456))
 	= "Two: x=123, y=456"
 	>> choose_text(Foo.Three(123, "hi", yes))
-	= "Three: Three(x=123, y=\"hi\", z=yes)"
+	= 'Three: Three(x=123, y="hi", z=yes)'
 	>> choose_text(Foo.Four(1,2,3,4))
 	= "Four"
 	>> choose_text(Foo.Last("XX"))
-	= "else: Foo.Last(\"XX\")"
+	= 'else: Foo.Last("XX")'
 
 	i := 1
 	cases := [Foo.One(1), Foo.One(2), Foo.Zero]
@@ -72,6 +72,3 @@ func main():
 	else:
 		-1
 	= 2
-
-
-

test/lang.tm

@@ -40,4 +40,4 @@ func main():
 	= $HTML"<p>Hello I &lt;3 hax!</p>"
 
 	>> Text(html)
-	= "$HTML\"Hello I &lt;3 hax!\""
+	= '$HTML"Hello I &lt;3 hax!"'

test/text.tm

@@ -20,7 +20,7 @@ func main():
 	= ["PENGUIN"]
 
 	>> \[31;1]
-	= "\e[31;1m"
+	= "$\e[31;1m"
 
 	>> \UE9 == \U65\U301
 	= yes
@@ -91,20 +91,20 @@ func main():
 		line one
 		line two
 	"
-	= "line one\nline two"
+	= "line one$\nline two"
 
 	!! Interpolation tests:
 	>> "A $(1+2)"
 	= "A 3"
 	>> 'A $(1+2)'
-	= "A $(1+2)"
+	= 'A $(1+2)'
 	>> `A $(1+2)`
 	= "A 3"
 
 	>> $"A $(1+2)"
 	= "A 3"
 	>> $$"A $(1+2)"
-	= "A $(1+2)"
+	= 'A $(1+2)'
 	>> $="A =(1+2)"
 	= "A 3"
 	>> ${one {nested} two $(1+2)}