Add more tests for multi-line strings and update docs

docs/markdown/Syntax.md

@@ -131,7 +131,8 @@ int main (int argc, char ** argv) {
 }'''
 ```
 
-This can also be combined with the string formatting functionality
+These are raw strings that do not support the escape sequences listed above.
+These strings can also be combined with the string formatting functionality
 described below.
 
 #### String formatting

docs/markdown/snippets/more-escape-sequences.md

@@ -1,17 +1,15 @@
-## String escape character update
+## String escape character sequence update
 
-The strings (both single-quoted and triple-quoted) in meson has been taught the
-same set of escape sequences as in Python. It is therefore now possible to use
-arbitrary bytes in strings, like for example NUL (`\0`) and other ASCII control
-characters. See the chapter about *Strings* in *Syntax* for more details.
+Single-quoted strings in meson have been taught the same set of escape
+sequences as in Python. It is therefore now possible to use arbitrary bytes in
+strings, like for example `NUL` (`\0`) and other ASCII control characters. See
+the chapter about [*Strings* in *Syntax*](Syntax.md#strings) for more
+details.
 
 Potential backwards compatibility issue: Any valid escape sequence according to
 the new rules will be interpreted as an escape sequence instead of the literal
-characters. Previously only single-quote strings supported escape sequences and
-the supported sequences were `\'`, `\\` and `\n`.
+characters. Previously only the following escape sequences were supported in
+single-quote strings: `\'`, `\\` and `\n`.
 
-The most likely breakage is usage of backslash-n in triple-quoted strings. It
-is now written in the same way as in single-quoted strings: `\\n` instead of
-`\n`. In general it is now recommended to escape any usage of backslash.
-However, backslash-c (`\c`), for example, is still backslash-c because it isn't
-a valid escape sequence.
+Note that the behaviour of triple-quoted (multiline) strings has not changed.
+They behave like raw strings and do not support any escape sequences.

test cases/common/32 multiline string/meson.build

@@ -23,3 +23,13 @@ quote2 = '\''
 if quote1 != quote2
   error('Single quote quoting is broken.')
 endif
+
+cc = meson.get_compiler('c')
+prog = '''
+int main(int argc, char **argv) {
+  int num = 1;
+  printf("%d\n", num);
+  return 0;
+}'''
+
+assert(cc.compiles(prog), 'multline test compile failed')

test cases/common/42 string operations/meson.build

@@ -87,6 +87,8 @@ bs_nl = '''\
 bs_bs_n = '''\\n'''
 bs_bs_nl = '''\\
 '''
+bs_bs = '''\\'''
+bs = '''\'''
 
 assert('\c' == bs_c, 'Single backslash broken')
 assert('\\c' == bs_c, 'Double backslash broken')
@@ -97,3 +99,5 @@ assert('\\n' == bs_n, 'Double backslash broken before n')
 assert('\\\n' == bs_nl, 'Three backslash broken before n')
 assert('\\\\n' == bs_bs_n, 'Four backslash broken before n')
 assert('\\\\\n' == bs_bs_nl, 'Five backslash broken before n')
+assert('\\\\' == bs_bs, 'Double-backslash broken')
+assert('\\' == bs, 'Backslash broken')