preprocessing tokens

1 files changed, 296 insertions, 9 deletions

diff --git a/05/preprocess.b b/05/preprocess.b
index 36fcbd2..ddc0c3b 100644
--- a/05/preprocess.b
+++ b/05/preprocess.b
@@ -6,10 +6,12 @@ function split_into_preprocessing_tokens
 	local file_contents
 	local pptokens
 	local p
+	local b
 	local c
 	local in
 	local out
 	local n
+	local line_number
 	
 	fd = open_r(filename)
 	file_contents = malloc(2000000)
@@ -19,6 +21,7 @@ function split_into_preprocessing_tokens
 		n = syscall(0, fd, p, 4096)
 		if n == 0 goto pptokens_read_loop_end
 		p += n
+		goto pptokens_read_loop
 	:pptokens_read_loop_end
 	
 	; okay we read the file. first, delete every backslash-newline sequence (phase 2)
@@ -56,20 +59,304 @@ function split_into_preprocessing_tokens
 	:backslashnewline_loop_end
 	*1out = 0
 	
+	; split file into preprocessing tokens, remove comments (phase 3)
+	; we're still doing the trick with newlines, this time for ones inside comments
+	; this is needed because the following is legal C:
+	;   #include/*
+	;     */<stdio.h>
+	; and is not equivalent to:
+	;   #include
+	;     <stdio.h>
+	newlines = 1
 	in = file_contents
-	
-	fputs(1, file_contents)
+	out = pptokens
+	line_number = 1
+	:pptokens_loop
+		c = *1in
+		if c == 10 goto pptokens_newline_loop
+		if c == 0 goto pptokens_loop_end
+		if c == 32 goto pptoken_space
+		if c == 9 goto pptoken_space
+		b = isdigit(c)
+		if b != 0 goto pptoken_number
+		b = isalpha_or_underscore(c)
+		if b != 0 goto pptoken_identifier
+		b = str_startswith(in, .str_comment_start)
+		if b != 0 goto pptoken_comment
+		; now we check for all the various operators and symbols in C
+		
+		if c == 59 goto pptoken_single_character ; semicolon
+		if c == '( goto pptoken_single_character
+		if c == ') goto pptoken_single_character
+		if c == '[ goto pptoken_single_character
+		if c == '] goto pptoken_single_character
+		if c == '{ goto pptoken_single_character
+		if c == '} goto pptoken_single_character
+		if c == ', goto pptoken_single_character
+		if c == '~ goto pptoken_single_character
+		if c == '? goto pptoken_single_character
+		if c == ': goto pptoken_single_character
+		if c == '" goto pptoken_string_or_char_literal
+		if c == '' goto pptoken_string_or_char_literal
+		b = str_startswith(in, .str_lshift_eq)
+		if b != 0 goto pptoken_3_chars
+		b = str_startswith(in, .str_rshift_eq)
+		if b != 0 goto pptoken_3_chars
+		b = str_startswith(in, .str_eq_eq)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_not_eq)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_gt_eq)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_lt_eq)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_plus_plus)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_minus_minus)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_plus_eq)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_minus_eq)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_times_eq)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_div_eq)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_remainder_eq)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_and_eq)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_or_eq)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_xor_eq)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_and_and)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_or_or)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_lshift)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_rshift)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_arrow)
+		if b != 0 goto pptoken_2_chars
+		b = str_startswith(in, .str_dotdotdot)
+		if b != 0 goto pptoken_3_chars
+		b = str_startswith(in, .str_hash_hash)
+		if b != 0 goto pptoken_2_chars
+		if c == '+ goto pptoken_single_character
+		if c == '- goto pptoken_single_character
+		if c == '* goto pptoken_single_character
+		if c == '/ goto pptoken_single_character
+		if c == '% goto pptoken_single_character
+		if c == '& goto pptoken_single_character
+		if c == '| goto pptoken_single_character
+		if c == '^ goto pptoken_single_character
+		if c == '> goto pptoken_single_character
+		if c == '< goto pptoken_single_character
+		if c == '! goto pptoken_single_character
+		if c == '= goto pptoken_single_character
+		if c == '# goto pptoken_single_character
+		if c == '. goto pptoken_dot
+		
+		goto bad_pptoken
+		
+		:pptoken_comment
+			; emit a space ("Each comment is replaced by one space character.")
+			*1out = 32
+			out += 1
+			*1out = 0
+			out += 1
+			; skip over comment
+			:pptoken_comment_loop
+				b = str_startswith(in, .str_comment_end)
+				if b != 0 goto pptoken_comment_loop_end
+				c = *1in
+				in += 1
+				if c == 0 goto unterminated_comment
+				if c == 10 goto pptoken_comment_newline
+				goto pptoken_comment_loop
+			:pptoken_comment_loop_end
+			in += 2 ; skip */
+			goto pptokens_loop
+			:pptoken_comment_newline
+				; keep line numbers correct
+				newlines += 1
+				goto pptoken_comment_loop
+		:pptoken_dot
+			; could just be a . or could be .3 -- we need to check if *(in+1) is a digit
+			p = in + 1
+			b = isdigit(*1p)
+			if b != 0 goto pptoken_number
+			; okay it's just a dot
+			goto pptoken_single_character
+		:pptoken_string_or_char_literal
+			local delimiter
+			local backslash
+			delimiter = c
+			backslash = 0
+			*1out = c
+			out += 1
+			in += 1
+			:pptoken_strchar_loop
+				c = *1in
+				*1out = c
+				in += 1
+				out += 1
+				if c == '\ goto pptoken_strchar_backslash
+				if c == 10 goto unterminated_string
+				if c == 0 goto unterminated_string
+				b = backslash
+				backslash = 0
+				if b == 1 goto pptoken_strchar_loop ; string can't end with an odd number of backslashes
+				if c == delimiter goto pptoken_strchar_loop_end
+				goto pptoken_strchar_loop
+				:pptoken_strchar_backslash
+					backslash ^= 1
+					goto pptoken_strchar_loop
+			:pptoken_strchar_loop_end
+			*1out = 0
+			out += 1
+			goto pptokens_loop
+		:pptoken_number
+			c = *1in
+			b = is_ppnumber_char(c)
+			if b == 0 goto pptoken_number_end
+			*1out = c
+			out += 1
+			in += 1
+			if c == 'e goto pptoken_number_e
+			if c == 'E goto pptoken_number_e
+			goto pptoken_number
+			:pptoken_number_e
+				c = *1in
+				if c == '+ goto pptoken_number_sign
+				if c == '- goto pptoken_number_sign
+				goto pptoken_number
+			:pptoken_number_sign
+				; special code to handle + - immediately following e
+				*1out = c
+				in += 1
+				out += 1
+				goto pptoken_number
+			:pptoken_number_end
+			*1out = 0
+			out += 1
+			goto pptokens_loop
+		:pptoken_identifier
+				c = *1in
+				b = isalnum_or_underscore(c)
+				if b == 0 goto pptoken_identifier_end
+				*1out = c
+				in += 1
+				out += 1
+				goto pptoken_identifier
+			:pptoken_identifier_end
+				*1out = 0
+				out += 1
+				goto pptokens_loop
+		:pptoken_space
+			; space character token
+			*1out = 32
+			in += 1
+			out += 1
+			*1out = 0
+			out += 1
+			goto pptokens_loop
+		:pptoken_single_character
+			; a single character preprocessing token, like {?}
+			*1out = c
+			in += 1
+			out += 1
+			*1out = 0
+			out += 1
+			goto pptokens_loop
+		:pptoken_2_chars
+			; two-character pptoken (e.g. ##)
+			*1out = c
+			in += 1
+			out += 1
+			*1out = *1in
+			in += 1
+			out += 1
+			*1out = 0
+			out += 1
+			goto pptokens_loop
+		:pptoken_3_chars
+			; three-character pptoken (e.g. >>=)
+			*1out = c
+			in += 1
+			out += 1
+			*1out = *1in
+			in += 1
+			out += 1
+			*1out = *1in
+			in += 1
+			out += 1
+			*1out = 0
+			out += 1
+			goto pptokens_loop
+		:pptokens_newline_loop
+			if newlines == 0 goto pptokens_newline_loop_end
+			; output a newline
+			*1out = 10
+			out += 1
+			*1out = 0
+			out += 1
+			line_number += 1
+			newlines -= 1
+			goto pptokens_newline_loop
+		:pptokens_newline_loop_end
+			newlines = 1
+			in += 1
+			goto pptokens_loop	
+	:pptokens_loop_end
 	
 	free(file_contents)
 	close(fd)
-	return
+	return pptokens
 	
 	:unterminated_comment
-		fputs(2, .str_unterminated_comment)
-		fputs(2, filename)
-		fputc(2, 10)
-		exit(1)
+		compile_error(filename, line_number, .str_unterminated_comment)
 	:str_unterminated_comment
-		string Unterminated comment in file
-		byte 32
+		string Unterminated comment.
+		byte 0
+	:unterminated_string
+		compile_error(filename, line_number, .str_unterminated_string)
+	:str_unterminated_string
+		string Unterminated string or character literal.
+		byte 0
+	:bad_pptoken
+		compile_error(filename, line_number, .str_bad_pptoken)
+	:str_bad_pptoken
+		string Bad preprocessing token.
 		byte 0
+
+; can the given character appear in a C89 ppnumber?
+function is_ppnumber_char
+	argument c
+	if c == '. goto return_1
+	if c < '0 goto return_0
+	if c <= '9 goto return_1
+	if c < 'A goto return_0
+	if c <= 'Z goto return_1
+	if c == '_ goto return_1
+	if c < 'a goto return_0
+	if c <= 'z goto return_1
+	goto return_0
+
+function print_pptokens
+	argument pptokens
+	local p
+	p = pptokens
+	:print_pptokens_loop
+		if *1p == 0 goto print_pptokens_loop_end
+		putc('{)
+		puts(p)
+		putc('})
+		p += strlen(p)
+		p += 1
+		goto print_pptokens_loop
+	:print_pptokens_loop_end
+	putc(10)
+	return