Implement . string constant for the current label scope (#1499)

test/asm/builtin-reserved.asm

@@ -11,5 +11,23 @@ REDEF _NARG = 78
 DEF _NARG EQUS "hello"
 REDEF _NARG EQUS "world"
 
-SECTION "test", ROM0
+SECTION "_NARG", ROM0
 _NARG:
+ENDSECTION
+
+ASSERT !DEF(.)
+
+PURGE .
+
+DEF . EQU 12
+REDEF . EQU 34
+
+DEF . = 56
+REDEF . = 78
+
+DEF . EQUS "hello"
+REDEF . EQUS "world"
+
+SECTION ".", ROM0
+.:
+ENDSECTION

test/asm/builtin-reserved.err

@@ -14,4 +14,20 @@ error: builtin-reserved.asm(12):
     '_NARG' is reserved for a built-in symbol
 error: builtin-reserved.asm(15):
     '_NARG' is reserved for a built-in symbol
-error: Assembly aborted (8 errors)!
+error: builtin-reserved.asm(20):
+    '.' not defined
+error: builtin-reserved.asm(22):
+    '.' is reserved for a built-in symbol
+error: builtin-reserved.asm(23):
+    '.' is reserved for a built-in symbol
+error: builtin-reserved.asm(25):
+    '.' is reserved for a built-in symbol
+error: builtin-reserved.asm(26):
+    '.' is reserved for a built-in symbol
+error: builtin-reserved.asm(28):
+    '.' is reserved for a built-in symbol
+error: builtin-reserved.asm(29):
+    '.' is reserved for a built-in symbol
+error: builtin-reserved.asm(32):
+    "." has no value outside of a label scope
+error: Assembly aborted (16 errors)!

test/asm/label-scope.asm

@@ -0,0 +1,12 @@
+ASSERT !DEF(@) && !DEF(.)
+
+PURGE @, .
+
+SECTION "test", ROM0[42]
+Foobar:
+
+PURGE @, .
+
+ASSERT DEF(@) && DEF(.) && DEF(Foobar)
+
+PRINTLN "PC: {#05X:@}; label scope: \"{.}\"; {.}: {#05X:{.}}"

test/asm/label-scope.err

@@ -0,0 +1,9 @@
+error: label-scope.asm(3):
+    '@' not defined
+error: label-scope.asm(3):
+    '.' not defined
+error: label-scope.asm(8):
+    Built-in symbol '@' cannot be purged
+error: label-scope.asm(8):
+    Built-in symbol '.' cannot be purged
+error: Assembly aborted (4 errors)!

test/asm/label-scope.out

@@ -0,0 +1 @@
+PC: $002A; label scope: "Foobar"; Foobar: $002A

test/asm/period.asm

@@ -2,4 +2,5 @@ section "period", rom0
 
 global1: db 1
 .local   db 2
-.        db 3
+.        db 3 ; this...
+global1  db 4 ; ...expands to this

test/asm/period.err

@@ -1,3 +1,5 @@
 error: period.asm(5):
-    syntax error, unexpected .
-error: Assembly aborted (1 error)!
+    syntax error, unexpected DB, expecting : or ::
+error: period.asm(6):
+    syntax error, unexpected DB, expecting : or ::
+error: Assembly aborted (2 errors)!

test/asm/undefined-builtins.asm

@@ -3,6 +3,11 @@ assert !DEF(@)
 println @
 println "{@}?"
 
+; not inside a label scope
+assert !DEF(.)
+println .
+println "{.}?"
+
 ; not inside a macro
 assert !DEF(_NARG)
 println _NARG
@@ -13,6 +18,11 @@ assert DEF(@)
 println @
 println "{@}!"
 
+LabelScope:
+assert DEF(.)
+println .
+println "{.}!"
+
 MACRO m
 	assert DEF(_NARG)
 	println _NARG

test/asm/undefined-builtins.err

@@ -3,7 +3,11 @@ error: undefined-builtins.asm(3):
 error: undefined-builtins.asm(4):
     Interpolated symbol "@" does not exist
 error: undefined-builtins.asm(8):
-    _NARG has no value outside of a macro
+    "." has no value outside of a label scope
 error: undefined-builtins.asm(9):
+    Interpolated symbol "." does not exist
+error: undefined-builtins.asm(13):
+    _NARG has no value outside of a macro
+error: undefined-builtins.asm(14):
     Interpolated symbol "_NARG" does not exist
-error: Assembly aborted (4 errors)!
+error: Assembly aborted (6 errors)!

test/asm/undefined-builtins.out

@@ -1,8 +1,12 @@
 $0
+?
+
 ?
 $0
 ?
 $42
 $42!
+$42
+LabelScope!
 $3
 $3!