formatting, strings, comments

lang/Makefile

@@ -25,6 +25,10 @@ test: test-bins
 	  "$$b" || exit $$?; \
 	done
 
+fmt: $(wildcard tests/*.rs)
+	@echo "Formatting test source files..."
+	rustfmt --edition 2024 $^
+
 # pattern rule: compile each .rs into a binary with the same base name
 $(TARGET_DIR)/tests/%: tests/%.rs | $(OBJ) $(TARGET_DIR)/tests
 	@echo "[$(RUSTC)] $< -> $@"
@@ -37,7 +41,7 @@ $(TARGET_DIR)/tests: $(TARGET_DIR)
 	mkdir -p $(TARGET_DIR)/tests
 
 $(TARGET_DIR)/%.o: src/%.asm | $(TARGET_DIR)
-	nasm -f elf64 -g $< -o $@
+	nasm -wreloc-abs -f elf64 -g $< -o $@
 
 $(BIN): $(OBJ) $(BIN_OBJ)
 	mold -run ld -o $(BIN) $(OBJ)

lang/src/tokeniser.asm

@@ -310,6 +310,12 @@ NUM_LEXEMES: dq 30
     TOKEN_NUMBER    equ 31
     LEX_NUMBER db "<number>"
     LEX_NUMBER_len equ $ - LEX_NUMBER
+    TOKEN_STRING    equ 32
+    LEX_STRING db "<string>"
+    LEX_STRING_len equ $ - LEX_STRING
+    TOKEN_COMMENT   equ 33
+    LEX_COMMENT db "<comment>"
+    LEX_COMMENT_len equ $ - LEX_COMMENT
     
 
 section .text
@@ -366,6 +372,108 @@ is_ident:
     pop rbp
     ret
 
+is_comment:
+    push rbp
+    mov rbp, rsp
+    push r12
+    push r13
+    push r14
+
+    mov rax, [rel cursor]
+    mov r12, [rel buffer]
+    mov r13, [rel buffer_len]
+    add r12, rax
+    sub r13, rax
+
+    mov dil, [r12]
+    cmp dil, '/'
+    jne .not_comment
+
+    mov r14, 1
+    cmp r14, r13
+    jge .not_comment
+    mov dil, [r12 + r14]
+    cmp dil, '/'
+    jne .not_comment
+.loop:
+    inc r14
+    cmp r14, r13
+    jge .comment
+    mov dil, [r12 + r14]
+    cmp dil, 10  ; newline
+    jne .loop
+.comment:
+    mov rax, [rel cursor]
+    add rax, r14
+    mov [rel cursor], rax
+    mov rax, r14
+    jmp .epilogue
+
+.not_comment:
+    xor rax, rax
+.epilogue:
+    pop r14
+    pop r13
+    pop r12
+    pop rbp
+    ret
+
+;; Strings are sequences of characters enclosed in double quotes
+;; Strings span multiple lines, and may in the future contain escape sequences
+is_string:
+    push rbp
+    mov rbp, rsp
+    push r12
+    push r13
+    push r14
+
+    mov rax, [rel cursor]
+    mov r12, [rel buffer]
+    mov r13, [rel buffer_len]
+    add r12, rax
+    sub r13, rax
+
+    mov dil, [r12]
+    cmp dil, '"'
+    jne .not_string
+
+    mov r14, 1
+.loop:
+    cmp r14, r13
+    jge .unterminated
+    mov dil, [r12 + r14]
+    cmp dil, '"'
+    je .string
+    cmp dil, 0x5c  ; backslash
+    je .escape
+    inc r14
+    jmp .loop
+.escape:
+    inc r14
+    cmp r14, r13
+    jge .unterminated
+    inc r14
+    jmp .loop
+.string:
+    mov rax, [rel cursor]
+    inc r14                 ; include closing quote
+    add rax, r14
+    mov [rel cursor], rax
+    mov rax, r14
+    jmp .epilogue
+.unterminated:
+;; TODO: report unterminated string error
+    mov rax, r14
+    jmp .epilogue
+.not_string:
+    xor rax, rax
+.epilogue:
+    pop r14
+    pop r13
+    pop r12
+    pop rbp
+    ret
+
 ;; Numbers are sequences of numeric characters, interspersed with underscores
 ;; The leading character must be numeric
 ;; In the future, numbers may be prefixed with '0x' for hexadecimal or '0b' for binary.
@@ -479,6 +587,23 @@ find_lexeme:
     ; }
 .start:
     push r12
+    ; test special tokens:
+    ; if buffer[cursor] == '"' {
+    call is_string
+    test rax, rax
+    jne .is_string
+    ; } else if buffer[cursor].is_numeric() {
+    call is_number
+    ;   return is_number();
+    test rax, rax
+    jne .is_number
+    ; } else if buffer[cursor..][..2] == "//" {
+    call is_comment
+    ;   // skip to end of line
+    test rax, rax
+    jne .is_comment
+    ; }
+.loop_init:
     mov r12, 1
     ; for 1..NUM_LEXEMES {
 .loop:
@@ -512,11 +637,6 @@ find_lexeme:
     test rax, rax
     ;         return TOKEN_IDENT;
     jne .is_ident
-    ;       } else if is_number() {
-    call is_number
-    test rax, rax
-    ;         return TOKEN_NUMBER;
-    jne .is_number
     ;       } else {
     mov rdi, [rsp + 8]
     mov rax, [rel cursor]
@@ -546,11 +666,6 @@ find_lexeme:
     test rax, rax
     ;   return TOKEN_IDENT;
     jne .is_ident
-    ; } else if is_number() {
-    call is_number
-    test rax, rax
-    ;   return TOKEN_NUMBER;
-    jne .is_number
     ; } else {
     ;   return TOKEN_EOF;
     mov rdi, [rsp + 8]
@@ -560,6 +675,7 @@ find_lexeme:
     pop r12
     pop rdi
     pop rbp
+    mov rax, rdi
     ret
 .is_ident:
     ; rax = len
@@ -575,3 +691,14 @@ find_lexeme:
     mov qword [rdi], TOKEN_NUMBER
     mov [rdi + 16], rax
     jmp .epilogue
+.is_string:
+    mov rdi, [rsp + 8]
+    mov qword [rdi], TOKEN_STRING
+    mov [rdi + 16], rax
+    jmp .epilogue
+.is_comment:
+
+    mov rdi, [rsp + 8]
+    mov qword [rdi], TOKEN_COMMENT
+    mov [rdi + 16], rax
+    jmp .epilogue

lang/tests/tokens.rs

@@ -12,7 +12,6 @@ impl PartialEq for Lexeme {
             // Identifiers and numbers compare both token and lexeme
             30 | 31 => self.0 == other.0 && self.1 == other.1,
             _ => self.0 == other.0,
-
         }
     }
 }
@@ -37,10 +36,9 @@ struct LexemeRaw {
 }
 impl AsLexeme for LexemeRaw {
     fn as_lexeme(self) -> Option<Lexeme> {
-        let Self {token, lexeme, len} = self;
+        let Self { token, lexeme, len } = self;
-        let slice = unsafe {core::str::from_utf8_unchecked(
+        let slice =
-            core::slice::from_raw_parts(
+            unsafe { core::str::from_utf8_unchecked(core::slice::from_raw_parts(lexeme, len)) };
-                lexeme, len))};
         match token {
             1.. => Some(Lexeme(token, slice)),
             _ => None,
@@ -94,7 +92,9 @@ fn main() {
         tokeniser_init(c"tests/tokens/keywords.l".as_ptr());
         eprintln!("ok.");
 
-        assert_eq!(&collect_tokens()[..], &[
+        assert_eq!(
+            &collect_tokens()[..],
+            &[
                 Lexeme(4, ""),
                 Lexeme(1, ""),
                 Lexeme(2, ""),
@@ -106,13 +106,16 @@ fn main() {
                 Lexeme(10, ""),
                 Lexeme(9, ""),
                 Lexeme(5, ""),
-        ][..]);
+            ][..]
+        );
 
         eprint!("Initializing tokeniser.. ");
         tokeniser_init(c"tests/tokens/delimiters.l".as_ptr());
         eprintln!("ok.");
 
-        assert_eq!(&collect_tokens()[..], &[
+        assert_eq!(
+            &collect_tokens()[..],
+            &[
                 Lexeme(19, ""),
                 Lexeme(18, ""),
                 Lexeme(28, ""),
@@ -124,13 +127,16 @@ fn main() {
                 Lexeme(23, ""),
                 Lexeme(22, ""),
                 Lexeme(15, ""),
-        ][..]);
+            ][..]
+        );
 
         eprint!("Initializing tokeniser.. ");
         tokeniser_init(c"tests/tokens/identifier.l".as_ptr());
         eprintln!("ok.");
 
-        assert_eq!(&collect_tokens()[..], &[
+        assert_eq!(
+            &collect_tokens()[..],
+            &[
                 Lexeme(30, "this-is-an-ident"),
                 Lexeme(30, "another_ident123"),
                 Lexeme(30, "_underscore_test"),
@@ -138,15 +144,19 @@ fn main() {
                 Lexeme(30, "number12345"),
                 Lexeme(30, "____"),
                 Lexeme(30, "_"),
-            Lexeme(17, ""), Lexeme(30, "leading-minus"),
+                Lexeme(17, ""),
+                Lexeme(30, "leading-minus"),
                 Lexeme(30, "trailing-minus-"),
-        ]);
+            ]
+        );
 
         eprint!("Initializing tokeniser.. ");
         tokeniser_init(c"tests/tokens/function.l".as_ptr());
         eprintln!("ok.");
 
-        assert_eq!(&collect_tokens()[..], &[
+        assert_eq!(
+            &collect_tokens()[..],
+            &[
                 Lexeme(4, ""),
                 Lexeme(30, "my-function"),
                 Lexeme(19, ""),
@@ -158,19 +168,61 @@ fn main() {
                 Lexeme(10, ""),
                 Lexeme(23, ""),
                 Lexeme(20, ""),
-        ]);
+            ]
+        );
+
+        eprint!("Initializing tokeniser.. ");
+        tokeniser_init(c"tests/tokens/comment.l".as_ptr());
+        eprintln!("ok.");
+
+        assert_eq!(
+            &collect_tokens()[..],
+            &[
+                Lexeme(33, ""),
+                Lexeme(4, ""),
+                Lexeme(30, "my-function"),
+                Lexeme(19, ""),
+                Lexeme(18, ""),
+                Lexeme(12, ""),
+                Lexeme(11, ""),
+                Lexeme(21, ""),
+                Lexeme(33, ""),
+                Lexeme(5, ""),
+                Lexeme(10, ""),
+                Lexeme(23, ""),
+                Lexeme(20, ""),
+            ]
+        );
 
         eprint!("Initializing tokeniser.. ");
         tokeniser_init(c"tests/tokens/number.l".as_ptr());
         eprintln!("ok.");
 
-        assert_eq!(&collect_tokens()[..], &[
+        assert_eq!(
+            &collect_tokens()[..],
+            &[
                 Lexeme(31, "1234"),
                 Lexeme(31, "123_345_"),
                 Lexeme(31, "1234____56"),
                 Lexeme(31, "1"),
                 Lexeme(31, "0"),
-            ]);
+            ]
+        );
+
+        eprint!("Initializing tokeniser.. ");
+        tokeniser_init(c"tests/tokens/strings.l".as_ptr());
+        eprintln!("ok.");
+
+        assert_eq!(
+            &collect_tokens()[..],
+            &[[
+                Lexeme(32, "\"this is a string\""),
+                Lexeme(32, "\"another\nstring\nspanning multiple\n   lines\""),
+                Lexeme(32, "\"string with a \\\"quoted\\\" word\""),
+                Lexeme(32, "\"a\""),
+                Lexeme(32, "\"\"")
+            ],]
+        );
 
         eprintln!("Finished tokenising.");
     }

lang/tests/tokens/comment.l

@@ -0,0 +1,5 @@
+// This is a comment line
+fn my-function() -> bool {
+  // This function always returns false
+  return false;
+}

lang/tests/tokens/strings.l

@@ -0,0 +1,8 @@
+"this is a string"
+"another
+string
+spanning multiple
+   lines"
+"string with a \"quoted\" word"
+"a"
+""