Restrict custom binary and graphics digits (#1693)

* Restrict custom binary and graphics digits

* Update documentation

* Fix build error

test/asm/invalid-opt.asm

@@ -1,5 +1,13 @@
 opt b123
+opt b_1
+opt b10
+opt b00
 opt g12345
+opt g012_
+opt g$123
+opt g0234
+opt gxxyy
+opt gxyzy
 opt pxy
 opt p1234
 opt Qxy

test/asm/invalid-opt.err

@@ -1,23 +1,39 @@
 error: invalid-opt.asm(1):
     Must specify exactly 2 characters for option 'b'
 error: invalid-opt.asm(2):
-    Must specify exactly 4 characters for option 'g'
+    Invalid digit for binary constant '_'
 error: invalid-opt.asm(3):
-    Invalid argument for option 'p'
+    Changed digit for binary constant '1'
 error: invalid-opt.asm(4):
-    Invalid argument for option 'p'
+    Repeated digit for binary constant '0'
 error: invalid-opt.asm(5):
-    Invalid argument for option 'Q'
+    Must specify exactly 4 characters for option 'g'
 error: invalid-opt.asm(6):
-    Invalid argument for option 'Q'
+    Invalid digit for graphics constant '_'
 error: invalid-opt.asm(7):
-    Argument for option 'Q' must be between 1 and 31
+    Invalid digit for graphics constant '$'
 error: invalid-opt.asm(8):
-    Argument to 'r' is out of range ("99999999999999999999999999")
+    Changed digit for graphics constant '2'
 error: invalid-opt.asm(9):
-    Must specify an argument for option 'W'
+    Repeated digit for graphics constant 'x'
 error: invalid-opt.asm(10):
-    syntax error, unexpected end of line, expecting string
+    Repeated digit for graphics constant 'y'
 error: invalid-opt.asm(11):
+    Invalid argument for option 'p'
+error: invalid-opt.asm(12):
+    Invalid argument for option 'p'
+error: invalid-opt.asm(13):
+    Invalid argument for option 'Q'
+error: invalid-opt.asm(14):
+    Invalid argument for option 'Q'
+error: invalid-opt.asm(15):
+    Argument for option 'Q' must be between 1 and 31
+error: invalid-opt.asm(16):
+    Argument to 'r' is out of range ("99999999999999999999999999")
+error: invalid-opt.asm(17):
+    Must specify an argument for option 'W'
+error: invalid-opt.asm(18):
+    syntax error, unexpected end of line, expecting string
+error: invalid-opt.asm(19):
     No entries in the option stack
-error: Assembly aborted (11 errors)!
+error: Assembly aborted (19 errors)!

test/asm/null-outside-string.asm

@@ -1,7 +1,7 @@
 SECTION "test", ROM0
 	; '\0' is not special here; it's lexed as a line continuation...
-	DEF foo\0bar EQU 42
-	db foo\0bar
+	DEF foo\0qux EQU 42
+	db foo\0qux
 	; ...just like any other non-whitespace character
 	DEF spam\Xeggs EQU 69
 	db spam\Xeggs

test/asm/opt-g.asm

@@ -1,4 +1,4 @@
 PRINTLN `pqpq_rsrs
 
-OPT g.x0X
-PRINTLN `.x.x_0X0X
+OPT g.xOX
+PRINTLN `.x.x_OXOX

test/asm/underscore-in-numeric-literal.asm

@@ -22,7 +22,7 @@ _1234::
 	dl 6_._283_185 ; fixed point
 	dw `0123_3210, `00_33_22_11_ ; gfx
 
-; underscores as digits
-	opt g_ABC, b_X
-	db %_X_X__XX
-	dw `_A_B_C__
+; underscores with custom digits
+	opt g.ABC, b.X
+	db %.X.X_..XX_
+	dw `.A.B_.C.._