Implement #"raw strings" (#1122)

Fixes #1121

test/asm/raw-strings.asm

@@ -0,0 +1,76 @@
+DEF q EQUS "\""
+
+	assert !strcmp( \
+		#"\t\1{s}\", \
+		"\\t\\1\{s}\\" )
+	assert !strcmp( \
+		#"\a,\b,\1,\2", \
+		"\\a,\\b,\\1,\\2" )
+	assert !strcmp( \
+		#"""new
+line""", \
+		"new\nline" )
+	assert !strcmp( \
+		#"""new\nline""", \
+		"""new\\nline""" )
+	assert !strcmp( \
+		#"/\w+(\+\w+)?@[a-z]+\.[a-z]{2,3}/i", \
+		"/\\w+(\\+\\w+)?@[a-z]+\\.[a-z]\{2,3}/i" )
+	assert !strcmp( \
+		#{q}{q}{q}rs", \
+		{q}\{q}\{q}rs" )
+	assert !strcmp( \
+		#"", \
+		"" )
+	assert !strcmp( \
+		#"""""", \
+		"""""" )
+
+MACRO test
+	REDEF raw EQUS \1
+	REDEF plain EQUS \2
+	assert !strcmp("{raw}", "{plain}")
+ENDM
+
+	; test lexing string literals within macro args
+	test \
+		#"\t\1{s}\", \
+		"\\t\\1\{s}\\"
+	test \
+		#"\a,\b,\1,\2", \
+		"\\a,\\b,\\1,\\2"
+	test \
+		#"""new,
+line""", \
+		"new,\nline"
+	test \
+		#"""new,\nline""", \
+		"""new,\\nline"""
+	test \
+		#"/\w+(\+\w+)?@[a-z]+\.[a-z]{2,3}/i", \
+		"/\\w+(\\+\\w+)?@[a-z]+\\.[a-z]\{2,3}/i"
+	test \
+		#{q}{q}{q}rs", \
+		{q}\{q}\{q}rs"
+	test \
+		#"", \
+		""
+	test \
+		#"""""", \
+		""""""
+
+MACRO echo
+	println "\#"
+ENDM
+
+DEF s EQUS "foo"
+	echo \
+		# "{s}", \
+		#"{s}", \ ; raw!
+		#raw"{s}", \
+		#/*comment*/"{s}"
+	echo \
+		# """{s}""", \
+		#"""{s}""", \ ; raw!
+		#raw"""{s}""", \
+		#/*comment*/"""{s}"""