Implement 'character' literals (#1747)

test/asm/character-literals.asm

@@ -0,0 +1,34 @@
+def s equs "d"
+
+charmap "A", 1
+charmap "B", 2
+charmap "c{s}e", 3
+charmap "F", 4, 5, 6
+charmap "'", 42
+charmap "\"", 1234
+charmap "\n\r\t\0", 1337
+charmap "',\",\\", 99
+
+MACRO char
+	assert (\1) == (\2)
+ENDM
+
+char 'A', 1
+char 'B', 2
+char 'c{s}e', 3
+char '\'', 42
+char '"', 1234
+char '\n\r\t\0', 1337
+char '\',",\\', 99
+
+char charval("c{s}e", 0), 'c{s}e'
+
+def v equs "\n\r\t\0"
+def x = '{v}'
+char x, '\n\r\t\0'
+
+; errors
+char '?', $3f ; ASCII
+char 'F', 0
+char 'ABF', 0
+char '\n\r\t', 0

test/asm/character-literals.err

@@ -0,0 +1,15 @@
+warning: character-literals.asm(31) -> character-literals.asm::char(13): [-Wunmapped-char]
+    Unmapped character '?'
+error: character-literals.asm(32) -> character-literals.asm::char(13):
+    Character literals must be a single charmap unit
+error: character-literals.asm(33) -> character-literals.asm::char(13):
+    Character literals must be a single charmap unit
+warning: character-literals.asm(34) -> character-literals.asm::char(13): [-Wunmapped-char]
+    Unmapped character '\n'
+warning: character-literals.asm(34) -> character-literals.asm::char(13): [-Wunmapped-char]
+    Unmapped character '\r'
+warning: character-literals.asm(34) -> character-literals.asm::char(13): [-Wunmapped-char]
+    Unmapped character '\t'
+error: character-literals.asm(34) -> character-literals.asm::char(13):
+    Character literals must be a single charmap unit
+Assembly aborted with 3 errors!

test/asm/garbage_sequence.asm

@@ -1,3 +1,3 @@
 assert 1 +# 1 == 2
-assert 2 '?* 2 == 4
-assert 3 **?''?##?? 3 == 27
+assert 2 ?<EFBFBD>* 2 == 4
+assert 3 **?<EFBFBD>?##?? 3 == 27

test/asm/garbage_sequence.err

@@ -1,9 +1,9 @@
 error: garbage_sequence.asm(1):
     Unknown character '#'
 error: garbage_sequence.asm(2):
-    Unknown characters ''', '?'
+    Unknown characters '?', 0xFF
 error: garbage_sequence.asm(3):
-    Unknown characters '?', ''', ''', '?'
+    Unknown characters '?', 0xFF, '?'
 error: garbage_sequence.asm(3):
     Unknown character '#'
 error: garbage_sequence.asm(3):