X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=lexer.c;h=d368aed847b9bd0ed00f36e7ea301d6230d4b923;hb=2fb66fd8bd2a5956ab2cad26978ccfb7e105d45f;hp=65c52a3b0302f4aea7b86b4c68cda90ccbc6a7d3;hpb=9634f9c53e95b6bdc7883228c5ec5147f3de4f8e;p=cparser

diff --git a/lexer.c b/lexer.c
index 65c52a3..d368aed 100644
--- a/lexer.c
+++ b/lexer.c
@@ -19,6 +19,8 @@
  */
 #include <config.h>
 
+#include "adt/strutil.h"
+#include "input.h"
 #include "diagnostic.h"
 #include "lexer.h"
 #include "symbol_t.h"
@@ -29,7 +31,6 @@
 #include "adt/util.h"
 #include "types.h"
 #include "type_t.h"
-#include "target_architecture.h"
 #include "parser.h"
 #include "warning.h"
 #include "lang_features.h"
@@ -44,25 +45,19 @@
 #include <strings.h>
 #endif
 
-//#define DEBUG_CHARS
-#define MAX_PUTBACK 3
+#define MAX_PUTBACK 16    // 3 would be enough, but 16 gives a nicer alignment
 #define BUF_SIZE    1024
 
-#if defined(_WIN32) || defined(__CYGWIN__)
-/* No strtold on windows and no replacement yet */
-#define strtold(s, e) strtod(s, e)
-#endif
-
-static utf32             c;
-static source_position_t lexer_pos;
-token_t                  lexer_token;
-static symbol_t         *symbol_L;
-static FILE             *input;
-static utf32             buf[BUF_SIZE + MAX_PUTBACK];
-static const utf32      *bufend;
-static const utf32      *bufpos;
-static strset_t          stringset;
-bool                     allow_dollar_in_symbol = true;
+static input_t           *input;
+static utf32              input_buf[BUF_SIZE + MAX_PUTBACK];
+static const utf32       *bufpos;
+static const utf32       *bufend;
+static utf32              c;
+static source_position_t  lexer_pos;
+token_t                   lexer_token;
+static symbol_t          *symbol_L;
+static strset_t           stringset;
+bool                      allow_dollar_in_symbol = true;
 
 /**
  * Prints a parse error message at the current token.
@@ -84,288 +79,17 @@ static NORETURN internal_error(const char *msg)
 	internal_errorf(&lexer_pos, "%s", msg);
 }
 
-static size_t read_block(unsigned char *const read_buf, size_t const n)
-{
-	size_t const s = fread(read_buf, 1, n, input);
-	if (s == 0) {
-		/* on OS/X ferror appears to return true on eof as well when running
-		 * the application in gdb... */
-		if (!feof(input) && ferror(input))
-			parse_error("read from input failed");
-		buf[MAX_PUTBACK] = EOF;
-		bufpos           = buf + MAX_PUTBACK;
-		bufend           = buf + MAX_PUTBACK + 1;
-	}
-	return s;
-}
-
-static void decode_iso_8859_1(void)
-{
-	unsigned char read_buf[BUF_SIZE];
-	size_t const s = read_block(read_buf, sizeof(read_buf));
-	if (s == 0)
-		return;
-
-	unsigned char const *src = read_buf;
-	unsigned char const *end = read_buf + s;
-	utf32               *dst = buf + MAX_PUTBACK;
-	while (src != end)
-		*dst++ = *src++;
-
-	bufpos = buf + MAX_PUTBACK;
-	bufend = dst;
-}
-
-static void decode_iso_8859_15(void)
-{
-	unsigned char read_buf[BUF_SIZE];
-	size_t const s = read_block(read_buf, sizeof(read_buf));
-	if (s == 0)
-		return;
-
-	unsigned char const *src = read_buf;
-	unsigned char const *end = read_buf + s;
-	utf32               *dst = buf + MAX_PUTBACK;
-	while (src != end) {
-		utf32 tc = *src++;
-		switch (tc) {
-			case 0xA4: tc = 0x20AC; break; // €
-			case 0xA6: tc = 0x0160; break; // Å 
-			case 0xA8: tc = 0x0161; break; // Å¡
-			case 0xB4: tc = 0x017D; break; // Ž
-			case 0xB8: tc = 0x017E; break; // ž
-			case 0xBC: tc = 0x0152; break; // Œ
-			case 0xBD: tc = 0x0153; break; // œ
-			case 0xBE: tc = 0x0178; break; // Ÿ
-		}
-		*dst++ = tc;
-	}
-
-	bufpos = buf + MAX_PUTBACK;
-	bufend = dst;
-}
-
-static void decode_utf8(void)
-{
-	static utf32  part_decoded_min_code;
-	static utf32  part_decoded_char;
-	static size_t part_decoded_rest_len;
-
-	do {
-		unsigned char read_buf[BUF_SIZE];
-		size_t const s = read_block(read_buf, sizeof(read_buf));
-		if (s == 0) {
-			if (part_decoded_rest_len > 0)
-				parse_error("incomplete input char at end of input");
-			return;
-		}
-
-		unsigned char const *src = read_buf;
-		unsigned char const *end = read_buf + s;
-		utf32               *dst = buf + MAX_PUTBACK;
-		utf32                decoded;
-		utf32                min_code;
-
-		if (part_decoded_rest_len != 0) {
-			min_code              = part_decoded_min_code;
-			decoded               = part_decoded_char;
-			size_t const rest_len = part_decoded_rest_len;
-			part_decoded_rest_len = 0;
-			switch (rest_len) {
-				case 4:  goto realign;
-				case 3:  goto three_more;
-				case 2:  goto two_more;
-				default: goto one_more;
-			}
-		}
-
-		while (src != end) {
-			if ((*src & 0x80) == 0) {
-				decoded = *src++;
-			} else if ((*src & 0xE0) == 0xC0) {
-				min_code = 0x80;
-				decoded  = *src++ & 0x1F;
-one_more:
-				if (src == end) {
-					part_decoded_min_code = min_code;
-					part_decoded_char     = decoded;
-					part_decoded_rest_len = 1;
-					break;
-				}
-				if ((*src & 0xC0) == 0x80) {
-					decoded = (decoded << 6) | (*src++ & 0x3F);
-				} else {
-					goto invalid_char;
-				}
-				if (decoded < min_code                      ||
-						decoded > 0x10FFFF                      ||
-						(0xD800 <= decoded && decoded < 0xE000) || // high/low surrogates
-						(0xFDD0 <= decoded && decoded < 0xFDF0) || // noncharacters
-						(decoded & 0xFFFE) == 0xFFFE) {            // noncharacters
-					parse_error("invalid byte sequence in input");
-				}
-			} else if ((*src & 0xF0) == 0xE0) {
-				min_code = 0x800;
-				decoded  = *src++ & 0x0F;
-two_more:
-				if (src == end) {
-					part_decoded_min_code = min_code;
-					part_decoded_char     = decoded;
-					part_decoded_rest_len = 2;
-					break;
-				}
-				if ((*src & 0xC0) == 0x80) {
-					decoded = (decoded << 6) | (*src++ & 0x3F);
-				} else {
-					goto invalid_char;
-				}
-				goto one_more;
-			} else if ((*src & 0xF8) == 0xF0) {
-				min_code = 0x10000;
-				decoded  = *src++ & 0x07;
-three_more:
-				if (src == end) {
-					part_decoded_min_code = min_code;
-					part_decoded_char     = decoded;
-					part_decoded_rest_len = 3;
-					break;
-				}
-				if ((*src & 0xC0) == 0x80) {
-					decoded = (decoded << 6) | (*src++ & 0x3F);
-				} else {
-					goto invalid_char;
-				}
-				goto two_more;
-			} else {
-invalid_char:
-				parse_error("invalid byte sequence in input");
-realign:
-				do {
-					++src;
-					if (src == end) {
-						part_decoded_rest_len = 4;
-						break;
-					}
-				} while ((*src & 0xC0) == 0x80 || (*src & 0xF8) == 0xF8);
-				continue;
-			}
-			*dst++ = decoded;
-		}
-
-		bufpos = buf + MAX_PUTBACK;
-		bufend = dst;
-	} while (bufpos == bufend);
-}
-
-static void decode_windows_1252(void)
-{
-	unsigned char read_buf[BUF_SIZE];
-	size_t const s = read_block(read_buf, sizeof(read_buf));
-	if (s == 0)
-		return;
-
-	unsigned char const *src = read_buf;
-	unsigned char const *end = read_buf + s;
-	utf32               *dst = buf + MAX_PUTBACK;
-	while (src != end) {
-		utf32 tc = *src++;
-		switch (tc) {
-			case 0x80: tc = 0x20AC; break; // €
-			case 0x82: tc = 0x201A; break; // ‚
-			case 0x83: tc = 0x0192; break; // ƒ
-			case 0x84: tc = 0x201E; break; // „
-			case 0x85: tc = 0x2026; break; // …
-			case 0x86: tc = 0x2020; break; // †
-			case 0x87: tc = 0x2021; break; // ‡
-			case 0x88: tc = 0x02C6; break; // ˆ
-			case 0x89: tc = 0x2030; break; // ‰
-			case 0x8A: tc = 0x0160; break; // Å 
-			case 0x8B: tc = 0x2039; break; // ‹
-			case 0x8C: tc = 0x0152; break; // Œ
-			case 0x8E: tc = 0x017D; break; // Ž
-			case 0x91: tc = 0x2018; break; // ‘
-			case 0x92: tc = 0x2019; break; // ’
-			case 0x93: tc = 0x201C; break; // “
-			case 0x94: tc = 0x201D; break; // ”
-			case 0x95: tc = 0x2022; break; // •
-			case 0x96: tc = 0x2013; break; // –
-			case 0x97: tc = 0x2014; break; // —
-			case 0x98: tc = 0x02DC; break; // ˜
-			case 0x99: tc = 0x2122; break; // ™
-			case 0x9A: tc = 0x0161; break; // Å¡
-			case 0x9B: tc = 0x203A; break; // ›
-			case 0x9C: tc = 0x0153; break; // œ
-			case 0x9E: tc = 0x017E; break; // ž
-			case 0x9F: tc = 0x0178; break; // Ÿ
-		}
-		*dst++ = tc;
-	}
-
-	bufpos = buf + MAX_PUTBACK;
-	bufend = dst;
-}
-
-typedef void (*decoder_t)(void);
-
-static decoder_t decoder = decode_utf8;
-
-typedef struct named_decoder_t {
-	char const *name;
-	decoder_t   decoder;
-} named_decoder_t;
-
-static named_decoder_t const decoders[] = {
-	{ "CP819",           decode_iso_8859_1   }, // offical alias
-	{ "IBM819",          decode_iso_8859_1   }, // offical alias
-	{ "ISO-8859-1",      decode_iso_8859_1   }, // offical alias
-	{ "ISO-8859-15",     decode_iso_8859_15  }, // offical name
-	{ "ISO8859-1",       decode_iso_8859_1   },
-	{ "ISO8859-15",      decode_iso_8859_15  },
-	{ "ISO_8859-1",      decode_iso_8859_1   }, // offical alias
-	{ "ISO_8859-15",     decode_iso_8859_15  }, // offical alias
-	{ "ISO_8859-1:1987", decode_iso_8859_1   }, // offical name
-	{ "Latin-9",         decode_iso_8859_15  }, // offical alias
-	{ "UTF-8",           decode_utf8         }, // offical name
-	{ "csISOLatin1",     decode_iso_8859_1   }, // offical alias
-	{ "cp1252",          decode_windows_1252 },
-	{ "iso-ir-100",      decode_iso_8859_1   }, // offical alias
-	{ "l1",              decode_iso_8859_1   }, // offical alias
-	{ "latin1",          decode_iso_8859_1   }, // offical alias
-	{ "windows-1252",    decode_windows_1252 }, // official name
-
-	{ NULL,              NULL                }
-};
-
-/** strcasecmp is not part of C99 so we need our own implementation here */
-static int my_strcasecmp(const char *s1, const char *s2)
-{
-	for ( ; *s1 != 0; ++s1, ++s2) {
-		if (tolower(*s1) != tolower(*s2))
-			break;
-	}
-	return (unsigned char)*s1 - (unsigned char)*s2;
-}
-
-void select_input_encoding(char const* const encoding)
-{
-	for (named_decoder_t const *i = decoders; i->name != NULL; ++i) {
-		if (my_strcasecmp(encoding, i->name) != 0)
-			continue;
-		decoder = i->decoder;
-		return;
-	}
-	fprintf(stderr, "error: input encoding \"%s\" not supported\n", encoding);
-}
-
 static inline void next_real_char(void)
 {
 	assert(bufpos <= bufend);
 	if (bufpos >= bufend) {
-		if (input == NULL) {
+		size_t n = decode(input, input_buf+MAX_PUTBACK, BUF_SIZE);
+		if (n == 0) {
 			c = EOF;
 			return;
 		}
-		decoder();
+		bufpos = input_buf + MAX_PUTBACK;
+		bufend = bufpos + n;
 	}
 	c = *bufpos++;
 	++lexer_pos.colno;
@@ -378,27 +102,23 @@ static inline void next_real_char(void)
  */
 static inline void put_back(utf32 const pc)
 {
-	assert(bufpos > buf);
-	*(--bufpos - buf + buf) = pc;
+	*(--bufpos - input_buf + input_buf) = pc;
 	--lexer_pos.colno;
-
-#ifdef DEBUG_CHARS
-	printf("putback '%lc'\n", pc);
-#endif
 }
 
 static inline void next_char(void);
 
-#define MATCH_NEWLINE(code)  \
-	case '\r':               \
-		next_char();         \
-		if (c == '\n') {     \
-	case '\n':               \
-			next_char();     \
-		}                    \
-		lexer_pos.lineno++;  \
+#define NEWLINE  \
+	'\r': \
+		next_char(); \
+		if (c == '\n') { \
+	case '\n': \
+			next_char(); \
+		} \
+		lexer_pos.lineno++; \
 		lexer_pos.colno = 1; \
-		code
+		goto newline; \
+		newline // Let it look like an ordinary case label.
 
 #define eat(c_type) (assert(c == c_type), next_char())
 
@@ -407,7 +127,8 @@ static void maybe_concat_lines(void)
 	eat('\\');
 
 	switch (c) {
-	MATCH_NEWLINE(return;)
+	case NEWLINE:
+		return;
 
 	default:
 		break;
@@ -428,17 +149,17 @@ static inline void next_char(void)
 	/* filter trigraphs */
 	if (UNLIKELY(c == '\\')) {
 		maybe_concat_lines();
-		goto end_of_next_char;
+		return;
 	}
 
 	if (LIKELY(c != '?'))
-		goto end_of_next_char;
+		return;
 
 	next_real_char();
 	if (LIKELY(c != '?')) {
 		put_back(c);
 		c = '?';
-		goto end_of_next_char;
+		return;
 	}
 
 	next_real_char();
@@ -458,11 +179,6 @@ static inline void next_char(void)
 		c = '?';
 		break;
 	}
-
-end_of_next_char:;
-#ifdef DEBUG_CHARS
-	printf("nchar '%c'\n", c);
-#endif
 }
 
 #define SYMBOL_CHARS  \
@@ -533,15 +249,103 @@ end_of_next_char:;
 	case '8':         \
 	case '9':
 
+static bool is_universal_char_valid(utf32 const v)
+{
+	/* C11 §6.4.3:2 */
+	if (v < 0xA0U && v != 0x24 && v != 0x40 && v != 0x60)
+		return false;
+	if (0xD800 <= v && v <= 0xDFFF)
+		return false;
+	return true;
+}
+
+static int digit_value(utf32 digit);
+
+static utf32 parse_universal_char(unsigned const n_digits)
+{
+	utf32 v = 0;
+	for (unsigned k = n_digits; k != 0; --k) {
+		if (isxdigit(c)) {
+			v = 16 * v + digit_value(c);
+			next_char();
+		} else {
+			errorf(&lexer_pos, "short universal character name, expected %u more digits", k);
+			break;
+		}
+	}
+	if (!is_universal_char_valid(v)) {
+		errorf(&lexer_pos, "\\%c%0*X is not a valid universal character name", n_digits == 4 ? 'u' : 'U', (int)n_digits, v);
+	}
+	return v;
+}
+
+static bool is_universal_char_valid_identifier(utf32 const v)
+{
+	/* C11 Annex D.1 */
+	if (                v == 0x000A8) return true;
+	if (                v == 0x000AA) return true;
+	if (                v == 0x000AD) return true;
+	if (                v == 0x000AF) return true;
+	if (0x000B2 <= v && v <= 0x000B5) return true;
+	if (0x000B7 <= v && v <= 0x000BA) return true;
+	if (0x000BC <= v && v <= 0x000BE) return true;
+	if (0x000C0 <= v && v <= 0x000D6) return true;
+	if (0x000D8 <= v && v <= 0x000F6) return true;
+	if (0x000F8 <= v && v <= 0x000FF) return true;
+	if (0x00100 <= v && v <= 0x0167F) return true;
+	if (0x01681 <= v && v <= 0x0180D) return true;
+	if (0x0180F <= v && v <= 0x01FFF) return true;
+	if (0x0200B <= v && v <= 0x0200D) return true;
+	if (0x0202A <= v && v <= 0x0202E) return true;
+	if (0x0203F <= v && v <= 0x02040) return true;
+	if (                v == 0x02054) return true;
+	if (0x02060 <= v && v <= 0x0206F) return true;
+	if (0x02070 <= v && v <= 0x0218F) return true;
+	if (0x02460 <= v && v <= 0x024FF) return true;
+	if (0x02776 <= v && v <= 0x02793) return true;
+	if (0x02C00 <= v && v <= 0x02DFF) return true;
+	if (0x02E80 <= v && v <= 0x02FFF) return true;
+	if (0x03004 <= v && v <= 0x03007) return true;
+	if (0x03021 <= v && v <= 0x0302F) return true;
+	if (0x03031 <= v && v <= 0x0303F) return true;
+	if (0x03040 <= v && v <= 0x0D7FF) return true;
+	if (0x0F900 <= v && v <= 0x0FD3D) return true;
+	if (0x0FD40 <= v && v <= 0x0FDCF) return true;
+	if (0x0FDF0 <= v && v <= 0x0FE44) return true;
+	if (0x0FE47 <= v && v <= 0x0FFFD) return true;
+	if (0x10000 <= v && v <= 0x1FFFD) return true;
+	if (0x20000 <= v && v <= 0x2FFFD) return true;
+	if (0x30000 <= v && v <= 0x3FFFD) return true;
+	if (0x40000 <= v && v <= 0x4FFFD) return true;
+	if (0x50000 <= v && v <= 0x5FFFD) return true;
+	if (0x60000 <= v && v <= 0x6FFFD) return true;
+	if (0x70000 <= v && v <= 0x7FFFD) return true;
+	if (0x80000 <= v && v <= 0x8FFFD) return true;
+	if (0x90000 <= v && v <= 0x9FFFD) return true;
+	if (0xA0000 <= v && v <= 0xAFFFD) return true;
+	if (0xB0000 <= v && v <= 0xBFFFD) return true;
+	if (0xC0000 <= v && v <= 0xCFFFD) return true;
+	if (0xD0000 <= v && v <= 0xDFFFD) return true;
+	if (0xE0000 <= v && v <= 0xEFFFD) return true;
+	return false;
+}
+
+static bool is_universal_char_valid_identifier_start(utf32 const v)
+{
+	/* C11 Annex D.2 */
+	if (0x0300 <= v && v <= 0x036F) return false;
+	if (0x1DC0 <= v && v <= 0x1DFF) return false;
+	if (0x20D0 <= v && v <= 0x20FF) return false;
+	if (0xFE20 <= v && v <= 0xFE2F) return false;
+	return true;
+}
+
 /**
  * Read a symbol from the input and build
  * the lexer_token.
  */
 static void parse_symbol(void)
 {
-	obstack_1grow(&symbol_obstack, (char) c);
-	next_char();
-
 	while (true) {
 		switch (c) {
 		DIGITS
@@ -550,6 +354,34 @@ static void parse_symbol(void)
 			next_char();
 			break;
 
+		case '\\':
+			next_char();
+			switch (c) {
+			{
+				unsigned n;
+			case 'U': n = 8; goto universal;
+			case 'u': n = 4; goto universal;
+universal:
+				next_char();
+				utf32 const v = parse_universal_char(n);
+				if (!is_universal_char_valid_identifier(v)) {
+					if (is_universal_char_valid(v)) {
+						errorf(&lexer_pos, "universal character \\%c%0*X is not valid in an identifier", n == 4 ? 'u' : 'U', (int)n, v);
+					}
+				} else if (obstack_object_size(&symbol_obstack) == 0 && !is_universal_char_valid_identifier_start(v)) {
+					errorf(&lexer_pos, "universal character \\%c%0*X is not valid as start of an identifier", n == 4 ? 'u' : 'U', (int)n, v);
+				} else {
+					obstack_grow_symbol(&symbol_obstack, v);
+				}
+				break;
+			}
+
+			default:
+				put_back(c);
+				c = '\\';
+				goto end_symbol;
+			}
+
 		default:
 dollar_sign:
 			goto end_symbol;
@@ -562,14 +394,32 @@ end_symbol:
 	char     *string = obstack_finish(&symbol_obstack);
 	symbol_t *symbol = symbol_table_insert(string);
 
-	lexer_token.type   = symbol->ID;
-	lexer_token.symbol = symbol;
+	lexer_token.kind        = symbol->ID;
+	lexer_token.base.symbol = symbol;
 
 	if (symbol->string != string) {
 		obstack_free(&symbol_obstack, string);
 	}
 }
 
+static string_t sym_make_string(string_encoding_t const enc)
+{
+	obstack_1grow(&symbol_obstack, '\0');
+	size_t const len    = obstack_object_size(&symbol_obstack) - 1;
+	char  *const string = obstack_finish(&symbol_obstack);
+
+	/* TODO hash */
+#if 0
+	const char *result = strset_insert(&stringset, concat);
+	if (result != concat) {
+		obstack_free(&symbol_obstack, concat);
+	}
+#else
+	const char *result = string;
+#endif
+	return (string_t){ result, len, enc };
+}
+
 /**
  * parse suffixes like 'LU' or 'f' after numbers
  */
@@ -589,32 +439,29 @@ static void parse_number_suffix(void)
 	}
 finish_suffix:
 	if (obstack_object_size(&symbol_obstack) == 0) {
-		lexer_token.symbol = NULL;
+		lexer_token.number.suffix.begin = NULL;
+		lexer_token.number.suffix.size  = 0;
 		return;
 	}
 
-	obstack_1grow(&symbol_obstack, '\0');
-	char     *string = obstack_finish(&symbol_obstack);
-	symbol_t *symbol = symbol_table_insert(string);
-
-	if (symbol->string != string) {
-		obstack_free(&symbol_obstack, string);
-	}
-	lexer_token.symbol = symbol;
+	lexer_token.number.suffix = sym_make_string(STRING_ENCODING_CHAR);
 }
 
-static string_t identify_string(char *string, size_t len)
+static void parse_exponent(void)
 {
-	/* TODO hash */
-#if 0
-	const char *result = strset_insert(&stringset, concat);
-	if (result != concat) {
-		obstack_free(&symbol_obstack, concat);
+	if (c == '-' || c == '+') {
+		obstack_1grow(&symbol_obstack, (char)c);
+		next_char();
+	}
+
+	if (isdigit(c)) {
+		do {
+			obstack_1grow(&symbol_obstack, (char)c);
+			next_char();
+		} while (isdigit(c));
+	} else {
+		errorf(&lexer_token.base.source_position, "exponent has no digits");
 	}
-#else
-	const char *result = string;
-#endif
-	return (string_t) {result, len};
 }
 
 /**
@@ -626,7 +473,6 @@ static void parse_number_hex(void)
 	bool is_float   = false;
 	bool has_digits = false;
 
-	assert(obstack_object_size(&symbol_obstack) == 0);
 	while (isxdigit(c)) {
 		has_digits = true;
 		obstack_1grow(&symbol_obstack, (char) c);
@@ -648,34 +494,42 @@ static void parse_number_hex(void)
 		is_float = true;
 		obstack_1grow(&symbol_obstack, (char) c);
 		next_char();
-
-		if (c == '-' || c == '+') {
-			obstack_1grow(&symbol_obstack, (char) c);
-			next_char();
-		}
-
-		while (isxdigit(c)) {
-			obstack_1grow(&symbol_obstack, (char) c);
-			next_char();
-		}
+		parse_exponent();
 	} else if (is_float) {
-		errorf(&lexer_token.source_position,
+		errorf(&lexer_token.base.source_position,
 		       "hexadecimal floatingpoint constant requires an exponent");
 	}
-	obstack_1grow(&symbol_obstack, '\0');
 
-	size_t  size   = obstack_object_size(&symbol_obstack) - 1;
-	char   *string = obstack_finish(&symbol_obstack);
-	lexer_token.literal = identify_string(string, size);
+	lexer_token.number.number = sym_make_string(STRING_ENCODING_CHAR);
+
+	lexer_token.kind = is_float ? T_FLOATINGPOINT : T_INTEGER;
+
+	if (!has_digits) {
+		errorf(&lexer_token.base.source_position, "invalid number literal '%S'", &lexer_token.number.number);
+		lexer_token.number.number.begin = "0";
+		lexer_token.number.number.size  = 1;
+	}
+
+	parse_number_suffix();
+}
+
+static void parse_number_bin(void)
+{
+	bool has_digits = false;
+
+	while (c == '0' || c == '1') {
+		has_digits = true;
+		obstack_1grow(&symbol_obstack, (char)c);
+		next_char();
+	}
 
-	lexer_token.type    =
-		is_float ? T_FLOATINGPOINT_HEXADECIMAL : T_INTEGER_HEXADECIMAL;
+	lexer_token.number.number = sym_make_string(STRING_ENCODING_CHAR);
+	lexer_token.kind          = T_INTEGER;
 
 	if (!has_digits) {
-		errorf(&lexer_token.source_position, "invalid number literal '0x%S'",
-		       &lexer_token.literal);
-		lexer_token.literal.begin = "0";
-		lexer_token.literal.size  = 1;
+		errorf(&lexer_token.base.source_position, "invalid number literal '%S'", &lexer_token.number.number);
+		lexer_token.number.number.begin = "0";
+		lexer_token.number.number.size  = 1;
 	}
 
 	parse_number_suffix();
@@ -688,19 +542,7 @@ static void parse_number_hex(void)
  */
 static bool is_octal_digit(utf32 chr)
 {
-	switch (chr) {
-	case '0':
-	case '1':
-	case '2':
-	case '3':
-	case '4':
-	case '5':
-	case '6':
-	case '7':
-		return true;
-	default:
-		return false;
-	}
+	return '0' <= chr && chr <= '7';
 }
 
 /**
@@ -713,15 +555,21 @@ static void parse_number(void)
 
 	assert(obstack_object_size(&symbol_obstack) == 0);
 	if (c == '0') {
+		obstack_1grow(&symbol_obstack, (char)c);
 		next_char();
 		if (c == 'x' || c == 'X') {
+			obstack_1grow(&symbol_obstack, (char)c);
 			next_char();
 			parse_number_hex();
 			return;
-		} else {
-			has_digits = true;
+		} else if (c == 'b' || c == 'B') {
+			/* GCC extension: binary constant 0x[bB][01]+.  */
+			obstack_1grow(&symbol_obstack, (char)c);
+			next_char();
+			parse_number_bin();
+			return;
 		}
-		obstack_1grow(&symbol_obstack, '0');
+		has_digits = true;
 	}
 
 	while (isdigit(c)) {
@@ -745,43 +593,29 @@ static void parse_number(void)
 		is_float = true;
 		obstack_1grow(&symbol_obstack, 'e');
 		next_char();
-
-		if (c == '-' || c == '+') {
-			obstack_1grow(&symbol_obstack, (char) c);
-			next_char();
-		}
-
-		while (isdigit(c)) {
-			obstack_1grow(&symbol_obstack, (char) c);
-			next_char();
-		}
+		parse_exponent();
 	}
 
-	obstack_1grow(&symbol_obstack, '\0');
-	size_t  size   = obstack_object_size(&symbol_obstack) - 1;
-	char   *string = obstack_finish(&symbol_obstack);
-	lexer_token.literal = identify_string(string, size);
+	lexer_token.number.number = sym_make_string(STRING_ENCODING_CHAR);
 
-	/* is it an octal number? */
 	if (is_float) {
-		lexer_token.type = T_FLOATINGPOINT;
-	} else if (string[0] == '0') {
-		lexer_token.type = T_INTEGER_OCTAL;
-
-		/* check for invalid octal digits */
-		for (size_t i= 0; i < size; ++i) {
-			char t = string[i];
-			if (t >= '8')
-				errorf(&lexer_token.source_position,
-				       "invalid digit '%c' in octal number", t);
-		}
+		lexer_token.kind = T_FLOATINGPOINT;
 	} else {
-		lexer_token.type = T_INTEGER;
+		lexer_token.kind = T_INTEGER;
+
+		if (lexer_token.number.number.begin[0] == '0') {
+			/* check for invalid octal digits */
+			for (size_t i= 0; i < lexer_token.number.number.size; ++i) {
+				char t = lexer_token.number.number.begin[i];
+				if (t >= '8')
+					errorf(&lexer_token.base.source_position, "invalid digit '%c' in octal number", t);
+			}
+		}
 	}
 
 	if (!has_digits) {
-		errorf(&lexer_token.source_position, "invalid number literal '%S'",
-		       &lexer_token.literal);
+		errorf(&lexer_token.base.source_position, "invalid number literal '%S'",
+		       &lexer_token.number.number);
 	}
 
 	parse_number_suffix();
@@ -895,10 +729,10 @@ static utf32 parse_escape_sequence(void)
 		if (c_mode & _GNUC)
 			return 27;   /* hopefully 27 is ALWAYS the code for ESCAPE */
 		break;
-	case 'u':
-	case 'U':
-		parse_error("universal character parsing not implemented yet");
-		return EOF;
+
+	case 'U': return parse_universal_char(8);
+	case 'u': return parse_universal_char(4);
+
 	default:
 		break;
 	}
@@ -907,209 +741,72 @@ static utf32 parse_escape_sequence(void)
 	return EOF;
 }
 
-/**
- * Concatenate two strings.
- */
-string_t concat_strings(const string_t *const s1, const string_t *const s2)
-{
-	const size_t len1 = s1->size - 1;
-	const size_t len2 = s2->size - 1;
-
-	char *const concat = obstack_alloc(&symbol_obstack, len1 + len2 + 1);
-	memcpy(concat, s1->begin, len1);
-	memcpy(concat + len1, s2->begin, len2 + 1);
-
-	return identify_string(concat, len1 + len2 + 1);
-}
-
 string_t make_string(const char *string)
 {
-	size_t      len   = strlen(string) + 1;
-	char *const space = obstack_alloc(&symbol_obstack, len);
-	memcpy(space, string, len);
-
-	return identify_string(space, len);
+	obstack_grow(&symbol_obstack, string, strlen(string));
+	return sym_make_string(STRING_ENCODING_CHAR);
 }
 
-static void grow_symbol(utf32 const tc)
+static void parse_string(utf32 const delim, token_kind_t const kind, string_encoding_t const enc, char const *const context)
 {
-	struct obstack *const o  = &symbol_obstack;
-	if (tc < 0x80U) {
-		obstack_1grow(o, tc);
-	} else if (tc < 0x800) {
-		obstack_1grow(o, 0xC0 | (tc >> 6));
-		obstack_1grow(o, 0x80 | (tc & 0x3F));
-	} else if (tc < 0x10000) {
-		obstack_1grow(o, 0xE0 | ( tc >> 12));
-		obstack_1grow(o, 0x80 | ((tc >>  6) & 0x3F));
-		obstack_1grow(o, 0x80 | ( tc        & 0x3F));
-	} else {
-		obstack_1grow(o, 0xF0 | ( tc >> 18));
-		obstack_1grow(o, 0x80 | ((tc >> 12) & 0x3F));
-		obstack_1grow(o, 0x80 | ((tc >>  6) & 0x3F));
-		obstack_1grow(o, 0x80 | ( tc        & 0x3F));
-	}
-}
-
-/**
- * Parse a string literal and set lexer_token.
- */
-static void parse_string_literal(void)
-{
-	eat('"');
+	eat(delim);
 
 	while (true) {
 		switch (c) {
 		case '\\': {
 			utf32 const tc = parse_escape_sequence();
-			if (tc >= 0x100) {
-				warningf(WARN_OTHER, &lexer_pos, "escape sequence out of range");
+			if (enc == STRING_ENCODING_CHAR) {
+				if (tc >= 0x100) {
+					warningf(WARN_OTHER, &lexer_pos, "escape sequence out of range");
+				}
+				obstack_1grow(&symbol_obstack, tc);
+			} else {
+				obstack_grow_symbol(&symbol_obstack, tc);
 			}
-			obstack_1grow(&symbol_obstack, tc);
 			break;
 		}
 
-		case EOF: {
-			errorf(&lexer_token.source_position, "string has no end");
-			lexer_token.type = T_ERROR;
-			return;
-		}
+		case NEWLINE:
+			errorf(&lexer_pos, "newline while parsing %s", context);
+			break;
 
-		case '"':
-			next_char();
+		case EOF:
+			errorf(&lexer_token.base.source_position, "EOF while parsing %s", context);
 			goto end_of_string;
 
 		default:
-			grow_symbol(c);
-			next_char();
-			break;
+			if (c == delim) {
+				next_char();
+				goto end_of_string;
+			} else {
+				obstack_grow_symbol(&symbol_obstack, c);
+				next_char();
+				break;
+			}
 		}
 	}
 
 end_of_string:
-
-	/* TODO: concatenate multiple strings separated by whitespace... */
-
-	/* add finishing 0 to the string */
-	obstack_1grow(&symbol_obstack, '\0');
-	const size_t  size   = (size_t)obstack_object_size(&symbol_obstack);
-	char         *string = obstack_finish(&symbol_obstack);
-
-	lexer_token.type    = T_STRING_LITERAL;
-	lexer_token.literal = identify_string(string, size);
-}
-
-/**
- * Parse a wide character constant and set lexer_token.
- */
-static void parse_wide_character_constant(void)
-{
-	eat('\'');
-
-	while (true) {
-		switch (c) {
-		case '\\': {
-			const utf32 tc = parse_escape_sequence();
-			grow_symbol(tc);
-			break;
-		}
-
-		MATCH_NEWLINE(
-			parse_error("newline while parsing character constant");
-			break;
-		)
-
-		case '\'':
-			next_char();
-			goto end_of_wide_char_constant;
-
-		case EOF: {
-			errorf(&lexer_token.source_position, "EOF while parsing character constant");
-			lexer_token.type = T_ERROR;
-			return;
-		}
-
-		default:
-			grow_symbol(c);
-			next_char();
-			break;
-		}
-	}
-
-end_of_wide_char_constant:;
-	obstack_1grow(&symbol_obstack, '\0');
-	size_t  size   = (size_t) obstack_object_size(&symbol_obstack) - 1;
-	char   *string = obstack_finish(&symbol_obstack);
-
-	lexer_token.type     = T_WIDE_CHARACTER_CONSTANT;
-	lexer_token.literal  = identify_string(string, size);
-
-	if (size == 0) {
-		errorf(&lexer_token.source_position, "empty character constant");
-	}
+	lexer_token.kind          = kind;
+	lexer_token.string.string = sym_make_string(enc);
 }
 
 /**
- * Parse a wide string literal and set lexer_token.
+ * Parse a string literal and set lexer_token.
  */
-static void parse_wide_string_literal(void)
+static void parse_string_literal(string_encoding_t const enc)
 {
-	parse_string_literal();
-	if (lexer_token.type == T_STRING_LITERAL)
-		lexer_token.type = T_WIDE_STRING_LITERAL;
+	parse_string('"', T_STRING_LITERAL, enc, "string literal");
 }
 
 /**
  * Parse a character constant and set lexer_token.
  */
-static void parse_character_constant(void)
+static void parse_character_constant(string_encoding_t const enc)
 {
-	eat('\'');
-
-	while (true) {
-		switch (c) {
-		case '\\': {
-			utf32 const tc = parse_escape_sequence();
-			if (tc >= 0x100) {
-				warningf(WARN_OTHER, &lexer_pos, "escape sequence out of range");
-			}
-			obstack_1grow(&symbol_obstack, tc);
-			break;
-		}
-
-		MATCH_NEWLINE(
-			parse_error("newline while parsing character constant");
-			break;
-		)
-
-		case '\'':
-			next_char();
-			goto end_of_char_constant;
-
-		case EOF: {
-			errorf(&lexer_token.source_position, "EOF while parsing character constant");
-			lexer_token.type = T_ERROR;
-			return;
-		}
-
-		default:
-			grow_symbol(c);
-			next_char();
-			break;
-
-		}
-	}
-
-end_of_char_constant:;
-	obstack_1grow(&symbol_obstack, '\0');
-	const size_t        size   = (size_t)obstack_object_size(&symbol_obstack)-1;
-	char         *const string = obstack_finish(&symbol_obstack);
-
-	lexer_token.type    = T_CHARACTER_CONSTANT;
-	lexer_token.literal = identify_string(string, size);
-
-	if (size == 0) {
-		errorf(&lexer_token.source_position, "empty character constant");
+	parse_string('\'', T_CHARACTER_CONSTANT, enc, "character constant");
+	if (lexer_token.string.string.size == 0) {
+		errorf(&lexer_token.base.source_position, "empty character constant");
 	}
 }
 
@@ -1135,10 +832,12 @@ static void skip_multiline_comment(void)
 			}
 			break;
 
-		MATCH_NEWLINE(break;)
+		case NEWLINE:
+			break;
 
 		case EOF: {
-			errorf(&lexer_token.source_position, "at end of file while looking for comment end");
+			errorf(&lexer_token.base.source_position,
+			       "at end of file while looking for comment end");
 			return;
 		}
 
@@ -1195,57 +894,43 @@ static inline void next_pp_token(void)
  */
 static void eat_until_newline(void)
 {
-	while (pp_token.type != '\n' && pp_token.type != T_EOF) {
+	while (pp_token.kind != '\n' && pp_token.kind != T_EOF) {
 		next_pp_token();
 	}
 }
 
-/**
- * Handle the define directive.
- */
-static void define_directive(void)
-{
-	lexer_next_preprocessing_token();
-	if (lexer_token.type != T_IDENTIFIER) {
-		parse_error("expected identifier after #define\n");
-		eat_until_newline();
-	}
-}
-
-/**
- * Handle the ifdef directive.
- */
-static void ifdef_directive(int is_ifndef)
-{
-	(void) is_ifndef;
-	lexer_next_preprocessing_token();
-	//expect_identifier();
-	//extect_newline();
-}
-
-/**
- * Handle the endif directive.
- */
-static void endif_directive(void)
-{
-	//expect_newline();
-}
-
 /**
  * Parse the line directive.
  */
 static void parse_line_directive(void)
 {
-	if (pp_token.type != T_INTEGER) {
+	if (pp_token.kind != T_INTEGER) {
 		parse_error("expected integer");
 	} else {
 		/* use offset -1 as this is about the next line */
-		lexer_pos.lineno = atoi(pp_token.literal.begin) - 1;
+		lexer_pos.lineno = atoi(pp_token.number.number.begin) - 1;
 		next_pp_token();
 	}
-	if (pp_token.type == T_STRING_LITERAL) {
-		lexer_pos.input_name = pp_token.literal.begin;
+	if (pp_token.kind == T_STRING_LITERAL && pp_token.string.string.encoding == STRING_ENCODING_CHAR) {
+		lexer_pos.input_name       = pp_token.string.string.begin;
+		lexer_pos.is_system_header = false;
 		next_pp_token();
+
+		/* attempt to parse numeric flags as outputted by gcc preprocessor */
+		while (pp_token.kind == T_INTEGER) {
+			/* flags:
+			 * 1 - indicates start of a new file
+			 * 2 - indicates return from a file
+			 * 3 - indicates system header
+			 * 4 - indicates implicit extern "C" in C++ mode
+			 *
+			 * currently we're only interested in "3"
+			 */
+			if (streq(pp_token.number.number.begin, "3")) {
+				lexer_pos.is_system_header = true;
+			}
+			next_pp_token();
+		}
 	}
 
 	eat_until_newline();
@@ -1276,57 +961,44 @@ typedef enum stdc_pragma_value_kind_t {
  */
 static void parse_pragma(void)
 {
-	bool unknown_pragma = true;
-
 	next_pp_token();
-	if (pp_token.symbol->pp_ID == TP_STDC) {
-		stdc_pragma_kind_t kind = STDC_UNKNOWN;
+	if (pp_token.kind != T_IDENTIFIER) {
+		warningf(WARN_UNKNOWN_PRAGMAS, &pp_token.base.source_position,
+		         "expected identifier after #pragma");
+		eat_until_newline();
+		return;
+	}
+
+	stdc_pragma_kind_t kind = STDC_UNKNOWN;
+	if (pp_token.base.symbol->pp_ID == TP_STDC && c_mode & _C99) {
 		/* a STDC pragma */
-		if (c_mode & _C99) {
-			next_pp_token();
+		next_pp_token();
 
-			switch (pp_token.symbol->pp_ID) {
-			case TP_FP_CONTRACT:
-				kind = STDC_FP_CONTRACT;
-				break;
-			case TP_FENV_ACCESS:
-				kind = STDC_FENV_ACCESS;
-				break;
-			case TP_CX_LIMITED_RANGE:
-				kind = STDC_CX_LIMITED_RANGE;
-				break;
-			default:
-				break;
+		switch (pp_token.base.symbol->pp_ID) {
+		case TP_FP_CONTRACT:      kind = STDC_FP_CONTRACT;      break;
+		case TP_FENV_ACCESS:      kind = STDC_FENV_ACCESS;      break;
+		case TP_CX_LIMITED_RANGE: kind = STDC_CX_LIMITED_RANGE; break;
+		default:                  break;
+		}
+		if (kind != STDC_UNKNOWN) {
+			next_pp_token();
+			stdc_pragma_value_kind_t value;
+			switch (pp_token.base.symbol->pp_ID) {
+			case TP_ON:      value = STDC_VALUE_ON;      break;
+			case TP_OFF:     value = STDC_VALUE_OFF;     break;
+			case TP_DEFAULT: value = STDC_VALUE_DEFAULT; break;
+			default:         value = STDC_VALUE_UNKNOWN; break;
 			}
-			if (kind != STDC_UNKNOWN) {
-				stdc_pragma_value_kind_t value = STDC_VALUE_UNKNOWN;
-				next_pp_token();
-				switch (pp_token.symbol->pp_ID) {
-				case TP_ON:
-					value = STDC_VALUE_ON;
-					break;
-				case TP_OFF:
-					value = STDC_VALUE_OFF;
-					break;
-				case TP_DEFAULT:
-					value = STDC_VALUE_DEFAULT;
-					break;
-				default:
-					break;
-				}
-				if (value != STDC_VALUE_UNKNOWN) {
-					unknown_pragma = false;
-				} else {
-					errorf(&pp_token.source_position, "bad STDC pragma argument");
-				}
+			if (value == STDC_VALUE_UNKNOWN) {
+				kind = STDC_UNKNOWN;
+				errorf(&pp_token.base.source_position, "bad STDC pragma argument");
 			}
 		}
-	} else {
-		unknown_pragma = true;
 	}
 	eat_until_newline();
-	if (unknown_pragma) {
-		warningf(WARN_UNKNOWN_PRAGMAS, &pp_token.source_position, "encountered unknown #pragma");
+	if (kind == STDC_UNKNOWN) {
+		warningf(WARN_UNKNOWN_PRAGMAS, &pp_token.base.source_position,
+		         "encountered unknown #pragma");
 	}
 }
 
@@ -1335,40 +1007,19 @@ static void parse_pragma(void)
  */
 static void parse_preprocessor_identifier(void)
 {
-	assert(pp_token.type == T_IDENTIFIER);
-	symbol_t *symbol = pp_token.symbol;
-
-	switch (symbol->pp_ID) {
-	case TP_include:
-		printf("include - enable header name parsing!\n");
-		break;
-	case TP_define:
-		define_directive();
-		break;
-	case TP_ifdef:
-		ifdef_directive(0);
-		break;
-	case TP_ifndef:
-		ifdef_directive(1);
-		break;
-	case TP_endif:
-		endif_directive();
-		break;
+	assert(pp_token.kind == T_IDENTIFIER);
+	switch (pp_token.base.symbol->pp_ID) {
 	case TP_line:
 		next_pp_token();
 		parse_line_directive();
 		break;
-	case TP_if:
-	case TP_else:
-	case TP_elif:
-	case TP_undef:
-	case TP_error:
-		/* TODO; output the rest of the line */
-		parse_error("#error directive: ");
-		break;
 	case TP_pragma:
 		parse_pragma();
 		break;
+	case TP_error:
+		/* TODO; output the rest of the line */
+		parse_error("#error directive");
+		break;
 	}
 }
 
@@ -1379,7 +1030,7 @@ static void parse_preprocessor_directive(void)
 {
 	next_pp_token();
 
-	switch (pp_token.type) {
+	switch (pp_token.kind) {
 	case T_IDENTIFIER:
 		parse_preprocessor_identifier();
 		break;
@@ -1404,7 +1055,7 @@ static void parse_preprocessor_directive(void)
 #define MAYBE(ch, set_type)                                \
 				case ch:                                   \
 					next_char();                           \
-					lexer_token.type = set_type;           \
+					lexer_token.kind = set_type;           \
 					return;
 
 /* must use this as last thing */
@@ -1412,7 +1063,7 @@ static void parse_preprocessor_directive(void)
 				case ch:                                   \
 					if (c_mode & mode) {                   \
 						next_char();                       \
-						lexer_token.type = set_type;       \
+						lexer_token.kind = set_type;       \
 						return;                            \
 					}                                      \
 					/* fallthrough */
@@ -1426,13 +1077,14 @@ static void parse_preprocessor_directive(void)
 
 #define ELSE(set_type)                                     \
 		ELSE_CODE(                                         \
-			lexer_token.type = set_type;                   \
+			lexer_token.kind = set_type;                   \
 		)
 
 void lexer_next_preprocessing_token(void)
 {
 	while (true) {
-		lexer_token.source_position = lexer_pos;
+		lexer_token.base.source_position = lexer_pos;
+		lexer_token.base.symbol          = NULL;
 
 		switch (c) {
 		case ' ':
@@ -1440,32 +1092,33 @@ void lexer_next_preprocessing_token(void)
 			next_char();
 			break;
 
-		MATCH_NEWLINE(
-			lexer_token.type = '\n';
+		case NEWLINE:
+			lexer_token.kind = '\n';
 			return;
-		)
 
-		SYMBOL_CHARS
+		SYMBOL_CHARS {
 			parse_symbol();
 			/* might be a wide string ( L"string" ) */
-			if (lexer_token.symbol == symbol_L) {
+			string_encoding_t const enc = STRING_ENCODING_WIDE;
+			if (lexer_token.base.symbol == symbol_L) {
 				switch (c) {
-					case '"':  parse_wide_string_literal();     break;
-					case '\'': parse_wide_character_constant(); break;
+				case '"':  parse_string_literal(enc);     break;
+				case '\'': parse_character_constant(enc); break;
 				}
 			}
 			return;
+		}
 
 		DIGITS
 			parse_number();
 			return;
 
 		case '"':
-			parse_string_literal();
+			parse_string_literal(STRING_ENCODING_CHAR);
 			return;
 
 		case '\'':
-			parse_character_constant();
+			parse_character_constant(STRING_ENCODING_CHAR);
 			return;
 
 		case '.':
@@ -1482,7 +1135,7 @@ void lexer_next_preprocessing_token(void)
 					ELSE_CODE(
 						put_back(c);
 						c = '.';
-						lexer_token.type = '.';
+						lexer_token.kind = '.';
 					)
 			ELSE('.')
 		case '&':
@@ -1535,7 +1188,7 @@ void lexer_next_preprocessing_token(void)
 							ELSE_CODE(
 								put_back(c);
 								c = '%';
-								lexer_token.type = '#';
+								lexer_token.kind = '#';
 							)
 					ELSE('#')
 			ELSE('%')
@@ -1580,6 +1233,17 @@ void lexer_next_preprocessing_token(void)
 			MAYBE('#', T_HASHHASH)
 			ELSE('#')
 
+		case '\\':
+			next_char();
+			if (c == 'U' || c == 'u') {
+				put_back(c);
+				c = '\\';
+				parse_symbol();
+			} else {
+				lexer_token.kind = '\\';
+			}
+			return;
+
 		case '?':
 		case '[':
 		case ']':
@@ -1590,21 +1254,19 @@ void lexer_next_preprocessing_token(void)
 		case '~':
 		case ';':
 		case ',':
-		case '\\':
-			lexer_token.type = c;
+			lexer_token.kind = c;
 			next_char();
 			return;
 
 		case EOF:
-			lexer_token.type = T_EOF;
+			lexer_token.kind = T_EOF;
 			return;
 
 		default:
 dollar_sign:
 			errorf(&lexer_pos, "unknown character '%c' found", c);
 			next_char();
-			lexer_token.type = T_ERROR;
-			return;
+			break;
 		}
 	}
 }
@@ -1613,12 +1275,12 @@ void lexer_next_token(void)
 {
 	lexer_next_preprocessing_token();
 
-	while (lexer_token.type == '\n') {
+	while (lexer_token.kind == '\n') {
 newline_found:
 		lexer_next_preprocessing_token();
 	}
 
-	if (lexer_token.type == '#') {
+	if (lexer_token.kind == '#') {
 		parse_preprocessor_directive();
 		goto newline_found;
 	}
@@ -1630,40 +1292,28 @@ void init_lexer(void)
 	symbol_L = symbol_table_insert("L");
 }
 
-void lexer_open_stream(FILE *stream, const char *input_name)
+static void input_error(unsigned delta_lines, unsigned delta_cols,
+                        const char *message)
 {
-	input                = stream;
-	lexer_pos.lineno     = 0;
-	lexer_pos.colno      = 0;
-	lexer_pos.input_name = input_name;
-
-	bufpos = NULL;
-	bufend = NULL;
-
-	/* place a virtual \n at the beginning so the lexer knows that we're
-	 * at the beginning of a line */
-	c = '\n';
+	lexer_pos.lineno += delta_lines;
+	lexer_pos.colno  += delta_cols;
+	errorf(&lexer_pos, "%s", message);
 }
 
-void lexer_open_buffer(const char *buffer, size_t len, const char *input_name)
+void lexer_switch_input(input_t *new_input, const char *input_name)
 {
-	input                = NULL;
 	lexer_pos.lineno     = 0;
 	lexer_pos.colno      = 0;
 	lexer_pos.input_name = input_name;
 
-#if 0 // TODO
-	bufpos = buffer;
-	bufend = buffer + len;
+	set_input_error_callback(input_error);
+	input  = new_input;
+	bufpos = NULL;
+	bufend = NULL;
 
 	/* place a virtual \n at the beginning so the lexer knows that we're
 	 * at the beginning of a line */
 	c = '\n';
-#else
-	(void)buffer;
-	(void)len;
-	panic("builtin lexing not done yet");
-#endif
 }
 
 void exit_lexer(void)
@@ -1675,6 +1325,6 @@ static __attribute__((unused))
 void dbg_pos(const source_position_t source_position)
 {
 	fprintf(stdout, "%s:%u:%u\n", source_position.input_name,
-	        source_position.lineno, source_position.colno);
+	        source_position.lineno, (unsigned)source_position.colno);
 	fflush(stdout);
 }