Handle string literals within macro arguments (#685)

Fixes #683 and #691

The lexer's raw mode for reading macro args already attempted
to handle semicolons inside string literals, versus outside ones
which start comments. This change reuses the same function for
reading string literals in normal and raw modes, also handling:

- Commas in strings versus between macro args
- Character escapes
- {Interpolations} and \1-\9 args inside vs. outside strings
- Multi-line string literals

Macro args now allow escaping '\', '"', and '\\'.

A consistent model for expanding macro args and interpolations,
within macro args, string literals, and normal context:

- "{S}" should always equal the contents of S
- "\1" should always act like quoting the value of \1

test/asm/macro-arg-in-string.asm

@@ -1,9 +1,12 @@
 print1: MACRO
+	if _NARG == 2
+		assert !STRCMP("\1", \2)
+	endc
 	PRINTLN "\1"
 ENDM
 
 	print1 John "Danger" Smith
-	print1 \\A\nB
+	print1 \\\\A\\nB\n, "\\\\A\\nB\n"
 	print1 C\
 D
 	print1 E\!F ; illegal character escape
@@ -15,3 +18,10 @@ ENDM
 
 s EQUS "hello"
 	iprint s
+
+symprint: MACRO
+	PRINTLN {\1}
+ENDM
+
+hello EQUS "\"goodbye\""
+	symprint s

test/asm/macro-arg-in-string.err

@@ -1,3 +1,3 @@
-ERROR: macro-arg-in-string.asm(9) -> macro-arg-in-string.asm::print1(2):
+ERROR: macro-arg-in-string.asm(12):
     Illegal character escape '!'
 error: Assembly aborted (1 errors)!

test/asm/macro-arg-in-string.out

@@ -1,6 +1,7 @@
 John "Danger" Smith
-\A
-B
+\\A\nB
+
 CD
-E\F
+E!F
 hello
+goodbye

test/asm/multi-line-strings.asm

@@ -21,7 +21,8 @@ printarg: MACRO
 ENDM
 
 	printarg "
-	printarg """
+	printarg """multi-line
+string argument"""
 
 EMPTY1 EQUS ""
 EMPTY2 EQUS "\ ; comment

test/asm/multi-line-strings.err

@@ -1,2 +1,5 @@
-warning: multi-line-strings.asm(34): [-Wuser]
+ERROR: multi-line-strings.asm(23):
+    Unterminated string
+warning: multi-line-strings.asm(35): [-Wuser]
     check the line number
+error: Assembly aborted (1 errors)!

test/asm/multi-line-strings.out

@@ -8,6 +8,8 @@ The multi-line string can contain:
 !
 arg <">
 arg (")
-arg <""">
-arg (""")
+arg <"""multi-line
+string argument""">
+arg ("""multi-line
+string argument""")
 ()

test/asm/quine.asm

@@ -0,0 +1,14 @@
+R:MACRO
+REPT _NARG
+PRINT STRSUB("\n\"\\ ENRST1ABCDFGHIMOPU_n#()+,:>",\1+1,1)
+SHIFT
+ENDR
+ENDM
+N:MACRO
+ R \#
+REPT _NARG
+PRINT"\1",STRSUB("\n,",(_NARG>1)+1,1)
+SHIFT
+ENDR
+ENDM
+ N 6,29,18,10,12,6,19,0,6,4,20,8,3,22,5,10,6,15,0,20,6,17,5,8,3,7,8,6,7,21,11,25,1,2,23,2,1,2,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,1,28,2,9,27,9,28,9,26,0,7,16,17,14,8,0,4,5,13,6,0,4,5,13,18,0,5,29,18,10,12,6,19,0,3,6,3,2,24,0,6,4,20,8,3,22,5,10,6,15,0,20,6,17,5,8,1,2,9,1,28,7,8,6,7,21,11,25,1,2,23,28,1,28,25,22,5,10,6,15,30,9,26,27,9,28,9,26,0,7,16,17,14,8,0,4,5,13,6,0,4,5,13,18,0,3,5,3

test/asm/quine.out

@@ -0,0 +1,14 @@
+R:MACRO
+REPT _NARG
+PRINT STRSUB("\n\"\\ ENRST1ABCDFGHIMOPU_n#()+,:>",\1+1,1)
+SHIFT
+ENDR
+ENDM
+N:MACRO
+ R \#
+REPT _NARG
+PRINT"\1",STRSUB("\n,",(_NARG>1)+1,1)
+SHIFT
+ENDR
+ENDM
+ N 6,29,18,10,12,6,19,0,6,4,20,8,3,22,5,10,6,15,0,20,6,17,5,8,3,7,8,6,7,21,11,25,1,2,23,2,1,2,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,1,28,2,9,27,9,28,9,26,0,7,16,17,14,8,0,4,5,13,6,0,4,5,13,18,0,5,29,18,10,12,6,19,0,3,6,3,2,24,0,6,4,20,8,3,22,5,10,6,15,0,20,6,17,5,8,1,2,9,1,28,7,8,6,7,21,11,25,1,2,23,28,1,28,25,22,5,10,6,15,30,9,26,27,9,28,9,26,0,7,16,17,14,8,0,4,5,13,6,0,4,5,13,18,0,3,5,3

test/asm/quine2.asm

@@ -0,0 +1,4 @@
+q: macro
+	println \1,"\1"
+endm
+	q "q: macro\n\tprintln \\1,\"\\1\"\nendm\n\tq "

test/asm/quine2.out

@@ -0,0 +1,4 @@
+q: macro
+	println \1,"\1"
+endm
+	q "q: macro\n\tprintln \\1,\"\\1\"\nendm\n\tq "

test/asm/raw-macro-args.asm

@@ -0,0 +1,38 @@
+printargs: MACRO
+	rept _NARG
+		println \1
+		shift
+	endr
+ENDM
+
+printlit: MACRO
+	rept _NARG
+		println "\1"
+		shift
+	endr
+ENDM
+
+NUM EQU 42
+STR EQUS "str\"ing"
+
+	printargs NUM
+	printargs "{d:NUM}"
+	printargs "{STR}", 16 ; comment 1
+	printargs "\"literal \\\"\\\\\\\"\""
+	printargs "literal \"\\\"", \ ; comment 2
+"""multi-"line"
+  ""string"" arg"""
+	printargs MUL(2.0\, 3.0)
+	printargs "unclosed
+
+	printlit NUM
+	printlit "{d:NUM}"
+	printlit "{STR}", 16 ; comment 3
+	printlit "\"literal \\\"\\\\\\\"\""
+	printlit "literal \"\\\"", \ ; comment 4
+"""multi-"line"
+  ""string"" arg"""
+	printlit MUL(2.0\, 3.0)
+	printlit this\n is\, \{not\} a\\n syntax\" error
+	printlit "unclosed
+	printlit """EOF

test/asm/raw-macro-args.err

@@ -0,0 +1,9 @@
+ERROR: raw-macro-args.asm(26):
+    Unterminated string
+ERROR: raw-macro-args.asm(26) -> raw-macro-args.asm::printargs(2) -> raw-macro-args.asm::printargs::REPT~1(3):
+    Unterminated string
+ERROR: raw-macro-args.asm(37):
+    Unterminated string
+ERROR: raw-macro-args.asm(38):
+    Unterminated string
+error: Assembly aborted (4 errors)!

test/asm/raw-macro-args.out

@@ -0,0 +1,23 @@
+$2A
+42
+str"ing
+$10
+"literal \"\\\""
+literal "\"
+multi-"line"
+  ""string"" arg
+$60000
+unclosed
+NUM
+"42"
+"str\"ing"
+16
+"\"literal \\\"\\\\\\\"\""
+"literal \"\\\""
+"""multi-"line"
+  ""string"" arg"""
+MUL(2.0, 3.0)
+this
+ is, {not} a\n syntax" error
+"unclosed
+"""EOF