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/*
* @LANG: c
* A mini C-like language scanner.
*/
#include <stdio.h>
#include <string.h>
#define IDENT_BUFLEN 256
%%{
machine clang;
# Function to buffer a character.
action bufChar {
if ( identLen < IDENT_BUFLEN ) {
identBuf[identLen] = fc;
identLen += 1;
}
}
# Function to clear the buffer.
action clearBuf {
identLen = 0;
}
# Functions to dump tokens as they are matched.
action ident {
identBuf[identLen] = 0;
printf("ident(%i): %s\n", curLine, identBuf);
}
action literal {
identBuf[identLen] = 0;
printf("literal(%i): %s\n", curLine, identBuf);
}
action float {
identBuf[identLen] = 0;
printf("float(%i): %s\n", curLine, identBuf);
}
action int {
identBuf[identLen] = 0;
printf("int(%i): %s\n", curLine, identBuf);
}
action hex {
identBuf[identLen] = 0;
printf("hex(%i): 0x%s\n", curLine, identBuf);
}
action symbol {
identBuf[identLen] = 0;
printf("symbol(%i): %s\n", curLine, identBuf);
}
# Alpha numberic characters or underscore.
alnumu = alnum | '_';
# Alpha charactres or underscore.
alphau = alpha | '_';
# Symbols. Upon entering clear the buffer. On all transitions
# buffer a character. Upon leaving dump the symbol.
symbol = ( punct - [_'"] ) >clearBuf $bufChar %symbol;
# Identifier. Upon entering clear the buffer. On all transitions
# buffer a character. Upon leaving, dump the identifier.
ident = (alphau . alnumu*) >clearBuf $bufChar %ident;
# Match single characters inside literal strings. Or match
# an escape sequence. Buffers the charater matched.
sliteralChar =
( extend - ['\\] ) @bufChar |
( '\\' . extend @bufChar );
dliteralChar =
( extend - ["\\] ) @bufChar |
( '\\' . extend @bufChar );
# Single quote and double quota literals. At the start clear
# the buffer. Upon leaving dump the literal.
sliteral = ('\'' @clearBuf . sliteralChar* . '\'' ) %literal;
dliteral = ('"' @clearBuf . dliteralChar* . '"' ) %literal;
literal = sliteral | dliteral;
# Whitespace is standard ws, newlines and control codes.
whitespace = any - 0x21..0x7e;
# Describe both c style comments and c++ style comments. The
# priority bump on tne terminator of the comments brings us
# out of the extend* which matches everything.
ccComment = '//' . extend* $0 . '\n' @1;
cComment = '/*' . extend* $0 . '*/' @1;
# Match an integer. We don't bother clearing the buf or filling it.
# The float machine overlaps with int and it will do it.
int = digit+ %int;
# Match a float. Upon entering the machine clear the buf, buffer
# characters on every trans and dump the float upon leaving.
float = ( digit+ . '.' . digit+ ) >clearBuf $bufChar %float;
# Match a hex. Upon entering the hex part, clear the buf, buffer characters
# on every trans and dump the hex on leaving transitions.
hex = '0x' . xdigit+ >clearBuf $bufChar %hex;
# Or together all the lanuage elements.
fin = ( ccComment |
cComment |
symbol |
ident |
literal |
whitespace |
int |
float |
hex );
# Star the language elements. It is critical in this type of application
# that we decrease the priority of out transitions before doing so. This
# is so that when we see 'aa' we stay in the fin machine to match an ident
# of length two and not wrap around to the front to match two idents of
# length one.
clang_main = ( fin $1 %0 )*;
# This machine matches everything, taking note of newlines.
newline = ( any | '\n' @{ curLine += 1; } )*;
# The final fsm is the lexer intersected with the newline machine which
# will count lines for us. Since the newline machine accepts everything,
# the strings accepted is goverened by the clang_main machine, onto which
# the newline machine overlays line counting.
main := clang_main & newline;
}%%
#include <stdio.h>
%% write data noerror;
char data[] =
"/*\n"
" * Copyright\n"
" */\n"
"\n"
"/* Aapl.\n"
" */\n"
"\n"
"#define _AAPL_RESIZE_H\n"
"\n"
"#include <assert.h>\n"
"\n"
"#ifdef AAPL_NAMESPACE\n"
"namespace Aapl {\n"
"#endif\n"
"#define LIN_DEFAULT_STEP 256\n"
"#define EXPN_UP( existing, needed ) \\\n"
" need > eng ? (ned<<1) : eing\n"
" \n"
"\n"
"/*@}*/\n"
"#undef EXPN_UP\n"
"#ifdef AAPL_NAMESPACE\n"
"#endif /* _AAPL_RESIZE_H */\n";
void test( char *buf )
{
int len = strlen( buf );
char *p = buf, *pe = buf + len;
char *eof = pe;
char identBuf[IDENT_BUFLEN+1];
int identLen;
int curLine;
int cs;
identLen = 0;
curLine = 1;
%% write init;
%% write exec;
if ( cs >= clang_first_final )
printf("ACCEPT\n");
else
printf("FAIL\n");
}
int main()
{
test(
"999 0xaAFF99 99.99 /*\n"
"*/ 'lksdj' //\n"
"\"\n"
"\n"
"literal\n"
"\n"
"\n"
"\"0x00aba foobardd.ddsf 0x0.9\n" );
test(
"wordwithnum00asdf\n"
"000wordfollowsnum,makes new symbol\n"
"\n"
"finishing early /* unfinished ...\n" );
test( data );
return 0;
}
#ifdef _____OUTPUT_____
int(1): 999
hex(1): 0xaAFF99
float(1): 99.99
literal(2): lksdj
literal(8):
literal
hex(8): 0x00aba
ident(8): foobardd
symbol(8): .
ident(8): ddsf
hex(8): 0x0
symbol(8): .
int(8): 9
ACCEPT
ident(1): wordwithnum00asdf
int(2): 000
ident(2): wordfollowsnum
symbol(2): ,
ident(2): makes
ident(2): new
ident(2): symbol
ident(4): finishing
ident(4): early
FAIL
symbol(8): #
ident(8): define
ident(8): _AAPL_RESIZE_H
symbol(10): #
ident(10): include
symbol(10): <
ident(10): assert
symbol(10): .
ident(10): h
symbol(10): >
symbol(12): #
ident(12): ifdef
ident(12): AAPL_NAMESPACE
ident(13): namespace
ident(13): Aapl
symbol(13): {
symbol(14): #
ident(14): endif
symbol(15): #
ident(15): define
ident(15): LIN_DEFAULT_STEP
int(15): 256
symbol(16): #
ident(16): define
ident(16): EXPN_UP
symbol(16): (
ident(16): existing
symbol(16): ,
ident(16): needed
symbol(16): )
symbol(16): \
ident(17): need
symbol(17): >
ident(17): eng
symbol(17): ?
symbol(17): (
ident(17): ned
symbol(17): <
symbol(17): <
int(17): 1
symbol(17): )
symbol(17): :
ident(17): eing
symbol(21): #
ident(21): undef
ident(21): EXPN_UP
symbol(22): #
ident(22): ifdef
ident(22): AAPL_NAMESPACE
symbol(23): #
ident(23): endif
ACCEPT
#endif
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