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.\" %FreeBSD: src/usr.bin/lex/lex.1,v 1.10.2.3 2001/09/30 12:40:04 dd Exp %
.\"
.\" $FreeBSD$
.TH FLEX 1 "April 1995" "Version 2.5"
.SH ̾
flex \- ®ʻϽϤġ
.SH 
.B flex
.B [\-bcdfhilnpstvwBFILTV78+? \-C[aefFmr] \-ooutput \-Pprefix \-Sskeleton]
.B [\-\-help \-\-version]
.I [filename ...]
.SH 
ܥޥ˥奢ϡ
ƥȤΥѥޥå󥰤Ԥץġ
.I flex
򰷤ޤ
ܥޥ˥奢ϥ塼ȥꥢȥեȤޤߤޤ:
.nf

    
        ġû

    ñ

    ϥեΥեޥå

    ѥ
        flex Ѥĥɽ

    ϤΥޥåˡ
        ޥå뤫ꤹ뵬§

    
        ѥ󤬥ޥå˲Ԥꤹˡ

    줿
        flex 륹ʤ˴ؤܺ;
        ϸˡ

    Ͼ
        ʤؤʸ̮Ƴȡ
        "ߥ˥" ˡ

    ʣϥХåե
        ʣϸ򰷤ˡ;
        եǤϤʤʸ󤫤饹󤹤ˡ

    եνΥ롼
        եν˥ޥå̤ʥ롼

    ¿ʥޥ
        ǻѲǽʥޥΤޤȤ

    桼Ѳǽ
        ǻѲǽͤΤޤȤ

    Yacc ȤΥ󥿥ե
        lex ʤ yacc ѡȤη

    ץ
        flex Υޥɥ饤󥪥ץȡ
        "%option" ǥ쥯ƥ

    ǽϢ
        ʤǽʸ¤®ˤˡ

    C++ ʤ
        C++ ʥ饹Τ
        (¸Ū) ǽ

    Lex  POSIX Ȥߴ
        AT&T lex  POSIX lex ɸ
        flex Ȥΰ㤤

    
        flex (⤷) Ϥ
        顼åǰ̣ΤǤʤ

    Ϣե
        flex Ѥե

     / Х
        flex δΤ

    Ϣ
        ġ˴ط¾Υɥ

    
        Ϣˡޤߤޤ

.fi
.SH 
.I flex

.I 
뤿ΥġǤ
ǡʤȤϡ
ƥλѥϤץǤ
.I flex
ϻꤷե롢⤷ϥե̾Ϳʤä
ɸϤ顢륹ʤεҤɤ߹ߤޤ
εҤϡ
ɽ C ɤΥڥηȤäƤޤ

.I 롼
ȸƤФޤ
.I flex
ϡϤȤ C ե
.B lex.yy.c
ޤ
.B yylex()
롼ޤ
Υեϥѥ뤵졢
.B \-ll
饤֥ȤȤ˥󥯤ơ
¹ԷȤʤޤ
¹ԷϤȡ
ɽޥå뤿
ϤϤޤ
ޥåΤ򸫤Ĥȡб C ɤ¹Ԥޤ
.SH ñ
ޤñ㤫顢
.I flex
λȤ򸫤ƹԤޤ礦

.I flex
Ϥϡ"username" Ȥʸ˽в񤦤ȥ桼Υ֤̾
ʤꤷƤޤ:
.nf

    %%
    username    printf( "%s", getlogin() );

.fi
ǥեȤǤϡ
.I flex
ʤ˥ޥåʤäƥȤϽϤ˥ԡޤΤǡ
"username" ŸʤϤϤ˥ԡ뤳Ȥ
ΥʤκǽŪʷ̤Ȥʤޤ
ϤˤϤĤΥ롼ޤ
"username" 
.I ѥ
Ǥꡢ"printf" 
.I 
Ǥ
"%%" ϥ롼λϤޤΰǤ
.PP
̤򸫤Ƹޤ礦:
.nf

    %{
            int num_lines = 0, num_chars = 0;
    %}

    %%
    \\n      ++num_lines; ++num_chars;
    .       ++num_chars;

    %%
    main()
            {
            yylex();
            printf( "# of lines = %d, # of chars = %d\\n",
                    num_lines, num_chars );
            }

.fi
ΥʤϤʸӹԿޤ
(ǽ̤𤹤Ǥ)
ǽιԤ 2 Ĥѿ "num_lines"  "num_chars" ޤ
ѿϡ2 ܤ "%%" θƤ
.B yylex()

.B main()
Υ롼󤫤饢ǽǤ
ˤ 2 ĤΥ롼뤬ޤ
1 ܤϲʸ ("\\n") ˥ޥåԿʸΥȤäޤ
⤦ 1 ĤϡʸʳƤʸ
("." ȤɽɽƤޤ)˥ޥåޤ
.PP
Ϥ⤦äʣǤ:
.nf

    /* scanner for a toy Pascal-like language */

    %{
    /* need this for the call to atof() below */
    #include <math.h>
    %}

    DIGIT    [0-9]
    ID       [a-z][a-z0-9]*

    %%

    {DIGIT}+    {
                printf( "An integer: %s (%d)\\n", yytext,
                        atoi( yytext ) );
                }

    {DIGIT}+"."{DIGIT}*        {
                printf( "A float: %s (%g)\\n", yytext,
                        atof( yytext ) );
                }

    if|then|begin|end|procedure|function        {
                printf( "A keyword: %s\\n", yytext );
                }

    {ID}        printf( "An identifier: %s\\n", yytext );

    "+"|"-"|"*"|"/"   printf( "An operator: %s\\n", yytext );

    "{"[^}\\n]*"}"     /* eat up one-line comments */

    [ \\t\\n]+          /* eat up whitespace */

    .           printf( "Unrecognized character: %s\\n", yytext );

    %%

    main( argc, argv )
    int argc;
    char **argv;
        {
        ++argv, --argc;  /* skip over program name */
        if ( argc > 0 )
                yyin = fopen( argv[0], "r" );
        else
                yyin = stdin;

        yylex();
        }

.fi
 Pascal Τ褦ʸñʥʤθǤ
ۤʤäפ
.I ȡ
դ𤷤ޤ
.PP
ξܺ٤ϡʹߤޤ
.SH ϥեΥեޥå
.I flex
ϥե 3 Ĥʬʤꡢ
.B %%
ʤԤˤʬޤ:
.nf

    
    %%
    롼
    %%
    桼

.fi
.I 
ʬϡʤñ㲽ñ
.I ̾
ȡ
.I Ͼ
Ȥʤޤ
.PP
̾ϼηǤ:
.nf

    ̾\ 

.fi
"̾" ϸǤꡢ
쥿 ('_') Ϥޤä 0 İʾΥ쥿'_''-'
(å)³ޤ
ϡ̾³ǽʸϤޤꡢޤ³ΤȤޤ
ϸ "{̾}" ǻȤǤ"()" Ÿޤ
㤨С
.nf

    DIGIT    [0-9]
    ID       [a-z][a-z0-9]*

.fi
ϡ
"DIGIT" ñο˥ޥåɽǤ
"ID" 쥿 0 İʾΥ쥿³ɽǤޤ
ǽФ뻲
.nf

    {DIGIT}+"."{DIGIT}*

.fi

.nf

    ([0-9])+"."([0-9])*

.fi
ƱǤꡢ1 İʾο '.' ³
0 İʾο³Τ˥ޥåޤ
.PP
.I flex
Ϥ
.I 롼
ϼηΰϢΥ롼뤫ʤޤ:
.nf

    ѥ\ \ \ 

.fi
ǡѥϥǥȤƤƤϤʤ餺
ƱԤϤޤɬפޤ
.PP
ѥȥξܺ٤ϸβ򸫤Ʋ
.PP
Ǹˡ桼ɤʬñˤΤޤޤη
.B lex.yy.c
˥ԡޤ
ʤƤӽФޤϸƤӽФտ롼Τ˻Ѥޤ
ʬϤäƤ̵Ƥ⹽ޤ;
̵ˤϡϥե 2 ܤ
.B %%
άǤޤ
.PP
ȥ롼ʬǤϡ
.I ǥȤ줿
ƥȤ
.B %{

.B %}
Ȥδ֤ΥƥȤϤΤޤޤηǽϤ˥ԡޤ
(κ %{} Ϻޤ)
%{} ϥǥȤƤʤԤ˸ɬפޤ
.PP
롼ʬǤϡ
ǽΥ롼˸륤ǥȤ줿⤷ %{} ʬΥƥȤϡ
롼˥ѿȡ
(θǤ)롼뤿Ӥ˼¹Ԥ륳ɤȤޤ
롼ʬ¾ΥǥȤ줿⤷ %{} ʬΥƥȤ
Ϥ˥ԡޤ
̣ϤƤ餺ѥ˥顼Ȥʤ뤫Τޤ
(λͤ
.I POSIX
ߴΤˤޤ; ¾ΤΤ褦ʻͤϰʹߤ򸫤Ʋ)
.PP
ʬ(롼ʬǤϤʤǤ)Ǥϡ
ǥȤƤʤ("/*" Ϥޤ) ϼ "*/" ޤ
Τޤޤηǥԡޤ
.SH ѥ
ϥեΥѥϳĥɽȤäƵҤޤ
ʲ˼ޤ:
.nf

    x          ʸ 'x' ˥ޥå
    .          ԤƤʸ(Х)
    [xyz]      "ʸ饹"; ξ硢'x', 'y', 'z' Τˤ
                 ޥåޤ
    [abj-oZ]   ϰϻޤ "ʸ饹"; ξ硢'a', 'b' 
                 'j'  'o' ޤǤǤդΥ쥿 'Z' ˥ޥåޤ
    [^A-Z]     "ʸ饹"; 饹˴ޤޤʤǤդʸ
                 ޥåޤ ξ硢'A'  'Z' ޤǤʸ
                 ְʳΡʸ˥ޥåޤ
    [^A-Z\\n]   ʸȲԤֽƤʸ
    r*         0 ⤷Ϥʾ rr Ǥդɽ
    r+         1 ⤷Ϥʾ r
    r?         0 ⤷ 1Ĥ r (֤ޤפ r)
    r{2,5}     2 Ĥ 5ĤޤǤ r
    r{2,}      2 İʾ r
    r{4}       礦 4  r
    {̾}     "̾" Ÿ
               (򻲾)
    "[xyz]\\"foo"
               ʸ [xyz]"foo
    \\X         X  'a', 'b', 'f', 'n', 'r', 't', 'v' Τ줫
                 ȤANSI-C Ǥ \\X βȤʤޤ
                 ʳξ硢ʸ 'X' ('*' Τ褦ʥڥ졼
                 ̣ǤäʸΤꤹݤ˻Ȥޤ)
    \\123       8ʿ 123 ɽʸ
    \\x2a       16ʿ 2a ɽʸ
    (r)        r ˥ޥå; () ̤ͥѤ뤿˻ѡ
                 (ʲ򻲾)


    rs         ɽ r ɽ s ³; Ϣ(concatenation)
                 ȸƤӤޤ


    r|s        r ⤷ s


    r/s         s ³ r
                 s ˥ޥåƥȤϤΥ롼 "ĹŬ" Ƚꤹ
                 ˤϴޤޤޤ󤬼¹Ԥ
                 Ϥᤵޤ
                  r ˥ޥåƥȤ򸫤ޤ
                 Υѥ "ʸ̮(trailing context)" ȸƤФޤ
                 (flex Τ˥ޥåǽ r/s ȹ礻ʣޤ;
                 "ʱʸ̮" ˤĤƤϡ
                 ʹߤΡ / Х εҤ򸫤Ʋ)
    ^r         Ƭˤ r(λϤޤ⤷
                 󤵤줿ԤαǤ)
    r$         ˤ r"r/\\n" (ԤǤ)
                 "r/\\n" ƱǤ

               flex  "" ɽ flex 򥳥ѥ뤷
               C ѥ餬᤹ '\\n' ȴ˰פ뤳Ȥ
               դƲ;
               Υƥ DOS Ǥ \\r Ϥ
               "r$" ɽŪ r/\\r\\n Ѥɬפޤ


    <s>r       Ͼ s ˤ r(ϾˤĤƤϰʲ
               )
    <s1,s2,s3>r
               ƱϾ s1, s2, s3 ΤǤ褤
    <*>r       ǤդγϾ rϾ¾ŪʤΤǤ褤


    <<EOF>>    եνλ
    <s1,s2><<EOF>>
               Ͼ郎 s1 ⤷ s2 ǤȤΥեνλ

.fi
ʸ饹ǤϡƤɽΥڥ졼ϡ
 ('\\') 
ʸ饹ڥ졼Ǥ '-'  ']' ȥ饹Ƭ '^' 
̤ʰ̣򼺤ȤդƲ
.PP
˵󤲤ɽ̤ͥˤäƥ롼פʬƤޤ
־Υ롼פǤ⤤ͥ٤ǡ
ֲΥ롼פ̤ͥǤ㤯ʤäƤޤ
롼ǤƱ̤ͥǤ㤨С
.nf

    foo|bar*

.fi

.nf

    (foo)|(ba(r*))

.fi
ƱǤʤʤ '*' ڥ졼Ϣͥ٤⤯
Ϣ ('|') ͥ٤⤤ǤΥѥ
ʸ "foo"
.I ⤷
ʸ "ba"  0 İʾ r ĤŤΤ
.I ɤˤ
ޥåޤ
"foo" ⤷ 0 İʾ "bar" ˥ޥå뤿ˤϼɽѤƲ:
.nf

    foo|(bar)*

.fi
0 İʾ "foo" ޤ "bar" ˥ޥå뤿ˤϼɽѤƲ:
.nf

    (foo|bar)*

.fi
.PP
ʸ⤷ʸϰϤ˲äʸ饹ʸ饹
.I ɽ
ޤߤޤ
ɽ
.B [:

.B :]
Υǥߥ˰Ϥޤޤ (ʸ饹 '['  ']' Ȥδ֤˸ɬפޤ;
¾Ǥʸ饹˸Ƥ⹽ޤ)
ͭɽϰʲ̤Ǥ:
.nf

    [:alnum:] [:alpha:] [:blank:]
    [:cntrl:] [:digit:] [:graph:]
    [:lower:] [:print:] [:punct:]
    [:space:] [:upper:] [:xdigit:]

.fi
ɽбɸ C 
.B isXXX
ؿŬ礹Ƥʸؼޤ㤨С
.B [:alnum:]

.B isalnum()
֤ʸؼޤ - ʤ٤ƤΥե٥åȤȿǤ
.B isblank(),
̵ƥǤϡflex 
.B [:blank:]
ȥ֤ޤ
.PP
㤨аʲɽƱǤ:
.nf

    [[:alnum:]]
    [[:alpha:][:digit:]]
    [[:alpha:]0-9]
    [a-zA-Z0-9]

.fi
ʤʸʸռʤ(
.B \-i
ե饰)
.B [:upper:]

.B [:lower:]

.B [:alpha:]
ƱǤ
.PP
ѥ˴ؤǤ:
.IP -
ʸ饹㤨о "[^A-Z]" 
"\\n" (⤷Ϥɽץ) Ū
ʸ饹˸Ƥ (㤨 "[^A-Z\\n]") 
.I Ԥ˥ޥåޤ
¾ɽġ뤬ʸ饹򰷤ˡȤϰۤʤޤ
ԹʤȤˤ̷Ū˳ΩƤޤ
Ԥ˥ޥåȤϡ
Ϥ̤ΥȤ¸ߤʤ [^"]* Τ褦ʥѥ
Τ˥ޥå뤳Ȥ̣ޤ
.IP -
롼ϱʸ̮('/' ڥ졼⤷ '$' ڥ졼)
⡹ĤƤޤ
Ͼ '^'  "<<EOF>>" ѥ
ѥκǽˤʤФʤ餺 '/', '$'
Ʊͤ () ˤ뤳ȤϽޤ
롼ƬǤϤʤ '^' ⤷ϥ롼νǤϤʤ '$' 
̤ʰ̣򼺤̾ʸȤưޤ
.IP
ʲ̵Ǥ:
.nf

    foo/bar$
    <sc1>foo<sc2>bar

.fi
Ԥ "foo/bar\\n" Ƚ񤱤ޤ
.IP
ʲǤ '$'  '^' Ȥ̾ʸȤưޤ:
.nf

    foo|(bar$)
    foo|^bar

.fi
"foo" ⤷ "Ԥ³ bar" ꤷϡ
ɽѤƲ (̤ '|' ưϸޤ):
.nf

    foo      |
    bar$     /* action goes here */

.fi
Ʊˡǡfoo ⤷ Ƭ bar ǽǤ
.SH ϤΥޥåˡ
ʤ¹Ԥȡ
ʤϤ򸫤ƥѥ˥ޥåʸõޤ
1 ¿ΥޥåդȡĹƥȤΥޥåѤޤ
(ʸ̮(trailing context rule)θʬĹ˴ޤߤޤ
ʬϤᤵޤ)
ƱĹΥޥå 2 İʾ師դ硢
.I flex
ϥեǺǽ˵Ҥ줿롼Ѥޤ
.PP
ޥåꤹȡޥåбƥ(
.I ȡ
ȸƤФޤ)Хʸݥ
.B yytext
ˤѲǽȤʤꡢĹХ
.B yyleng
ˤѲǽȤʤޤ
θ塢ޥåѥб
.I 
¹Ԥ(ξܺ٤ʵҤϸǹԤޤ)
ĤϤĤΥޥåΤ˥󤵤ޤ
.PP
ޥåդʤȡ
.I ǥեȥ롼
¹Ԥޤ: Ϥμʸޥåȸ蘆졢
ɸϤ˥ԡޤǤñ
.I flex
Ϥϰʲ̤Ǥ:
.nf

    %%

.fi
ϡϤñ˽Ϥ˥ԡ(1 ٤ 1 ʸ)륹ʤޤ
.PP
.B yytext
 2 Ĥΰۤʤäˡˤ줦뤳ȤդƲ: ʸ
.I ݥ
⤷ʸ
.I 
Ǥ
.I flex
ɤѤ뤫̤ʥǥ쥯ƥ
.B %pointer
⤷
.B %array
 flex Ϥκǽ()ʬ˴ޤ뤳ȤˤǤޤ
ǥեȤ
.B %pointer
Ǥꡢ
.B -l
lex ߴץѤˤ㳰Ū
.B yytext
ˤʤޤ
.B %pointer
Ѥϥ󤬹®Ǥ뤳ȡ
礭ʥȡ˥ޥåˤ
(ưŪѤԤʤ¤)ХåեХեȤʤʤȤǤ
ϡ
.B yytext
뤳Ȥ¤뤳(Ỳ)
.B unput()
ƤӽФ
.B yytext
θߤƤ˲뤳ȤǤ
ϰۤʤ
.I lex
С֤Ǥΰܿ˴ؤƬˤμǤ
.PP
.B %array

.B yytext
Ƥפä̤ѹǤ뤳ȡ
.B unput()
ƤӽФƤ
.B yytext
Ƥ˲ʤȤǤ()
ξ塢¸
.I lex
ץ
.B yytext
鼡ηѤƥƤ뤳Ȥޤ:
.nf
    extern char yytext[];
.fi

.B %pointer
ѻˤϸǤ
.B %array
ѻˤǤ
.PP
.B %array

.B yytext
ʸ
.B YYLMAX
(ǥեȤϽʬ礭)Ǥޤ
礭ϡ
.I flex
Ϥκǽʬñ
.B YYLMAX
ۤʤäͤ #define 뤳ȤˤѹǤޤ
嵭̤ꡢ
.B %pointer
ѻˤ yytext 礭ʥȡǼ뤿ưŪ礭ʤޤ
ΤȤ
.B %pointer
Ѥʤ礭ʥȡ
(㤨Хȥ֥å)ǼǽǤ뤳Ȥ̣ޤ
ʤ
.B yytext
礭Ѥ뤿Ӥ˥ȡΤƬƥ󤹤뤳ȤɬפȤʤ뤿
Τ褦ʥȡФޥå󥰤٤ʤꤦ뤳ȤФƤƲ
ߡ
.B yytext

.B unput()
̤Ȥ֤ƥȤ礭ˤưŪˤ礭ʤ
.I ޤ;
¹Ի顼Ȥʤޤ
.PP
ޤ
.B %array

C++ ʥ饹ǤϻѤǤʤȤդƲ(
.B c++
ץ˴ؤƤϲ)
.SH 
롼Υѥб륢ޤ
Ǥդ C ʸǤ
ѥϺǽΥפƤʤʸǽޤ;
ԤλĤ꤬Ǥ
󤬶Ǥ硢
ѥ󤬥ޥåϥȡñ˼ΤƤޤ
㤨ϤƤ "zap me" ץλͤ򼨤ޤ:
.nf

    %%
    "zap me"

.fi
(Ϥ¾ƤʸϤ˥ԡޤ
ʤʤǥեȥ롼˥ޥå뤫Ǥ)
.PP
ϡʣζʸñζ˰̤ζΤƤץǤ:
.nf

    %%
    [ \\t]+        putchar( ' ' );
    [ \\t]+$       /* ignore this token */

.fi
.PP
 '{' ޤ硢б '}' ޤ³
ʣԤϤ⤢ޤ
.I flex
 C ʸ󤪤ӥȤ˴ؤΤäƤꡢ
Υ֥졼򤹤뤳ȤϤޤ󤬡

.B %{
ǻϤޤ뤳Ȥ
.B %}
ޤǤΥƥȤǤȤޤ
(ǤոĤΥ֥졼ˤϴطޤ)
.PP
ľС ('|') Τߤʤ륢
"Υ롼Ʊ" ̣ޤϰʲ򸫤Ʋ
.PP
Ǥդ C ɤޤळȤޤ
ˤϡ
.B yylex()
ƤӽФ롼Ф֤ͤ
.B return
ʸޤޤޤ
.B yylex()
ƤФ뤿ӡǸ˻Ĥäȡ󤫤Ƴ
եνλ⤷ return ¹ԤޤǽԤޤ
.PP
ϼͳ
.B yytext
ѹǤޤ㳰Ĺ䤹ȤǤ
(ʸ˲ä뤳Ȥˤʤꡢ
ϥȥ꡼θ³ʸ񤭤ޤ)

.B %array
ѻˤƤϤޤޤ(); ξ
.B yytext
ͳѹǤޤ
.PP
ϼͳ
.B yyleng
ѹǤޤ
.B yymore()
Ѥˤ㳰ŪѹƤϤޤ()
.PP
¿̤ʥǥ쥯ƥ֤ꡢ˴ޤ뤳Ȥޤ:
.IP -
.B ECHO
yytext 򥹥ʤνϤ˥ԡޤ
.IP -
.B BEGIN
˳Ͼ̾񤯤ȡʤб볫Ͼꤷޤ()
.IP -
.B REJECT
(⤷ϤƬ) "2 ܤˤ褯(second best)" ޥå롼
˿ʤ褦˥ʤ˻ؼޤ
"ϤΥޥåˡ" Ǽ褦˥롼򤵤졢
.B yytext

.B yyleng
Ŭڤꤵޤ
򤵤롼ϡǽ򤵤줿롼ƱĹǤ뤬
.I flex
ϥեˤƸǽФΡ⤷Ͼʤʸ˥ޥåΤǤ
㤨мǤθ
"frob" դ뤿Ӥ˥롼 special() ƤӤޤ:
.nf

            int word_count = 0;
    %%

    frob        special(); REJECT;
    [^ \\t\\n]+   ++word_count;

.fi
.B REJECT
̵硢
 "frob" ϸȤƿ줺
ʤ̤̾ȡ 1 ĤΥԤޤ
ʣ
.B REJECT
ѲǽǤꡢ줾츽ͭʥ롼μɤդޤ
㤨мΥʤϡ"abcd" Ȥȡ򥹥󤷡
Ϥ "abcdabcaba" 񤭤ޤ:
.nf

    %%
    a        |
    ab       |
    abc      |
    abcd     ECHO; REJECT;
    .|\\n     /* eat up any unmatched character */

.fi
( 3 ĤΥ롼 4 ܤΥ롼Υͭޤ
ʤʤ̤ '|' 󤬻ѤƤ뤫Ǥ)
.B REJECT
ϥʤǽȤä˥ȤΤ뵡ǽǤ;
⤷ʤΥ
.I 줫
ˤǤ REJECT Ȥ줿ʤ顢ʤ
.I Ƥ
ޥå®٤㲼ȤȤǤ

.B REJECT
򥪥ץ
.I -Cf

.I -CF
ȶѤ뤳ȤϽޤ
.IP
ޤ¾̥Ȱ㤤
.B REJECT

.I ʬ(branch)
Ǥ뤳ȤդƤ; ʤ REJECT ľΥ
¹
.I ޤ
.IP -
.B yymore()
˥롼ȥޥåȤˤϡбȡϡ
ߤ
.B yytext
Ƥ촹ΤǤϤʤ
.B yytext

.I ɲ
褦ʤ˻ؼޤ
㤨С "mega-kludge" Ϳȡʲ
"mega-mega-kludge" Ϥ˽񤭤ޤ:
.nf

    %%
    mega-    ECHO; yymore();
    kludge   ECHO;

.fi
ǽ "mega-" ϥޥåϤ˥ޤ
 "kludge" ޥåޤľ "mega-" ޤ
.B yytext
Ƭ˻ĤäƤꡢ"kludge" 
.B ECHO
롼ϼºݤˤ "mage-kludge" 񤭤ޤ
.PP
.B yymore()
λѤ˴ؤ 2 Ĥޤ
ޤ
.B yymore()
ϸߤΥȡ礭ȿǤ
.I yyleng
ͤΤ˰¸뤳ȤǤꡢ
.B yymore()
ѻˤ
.I yyleng
ѹƤϤʤޤ
ˡ
ʤΥ
.B yymore()
ȡʤΥޥå®٤˼㴳ƶޤ
.IP -
.B yyless(n)
ߤΥȡ󤫤ǽ
.I n
ʸΤϥȥ꡼ᤷޤ
ᤷʸϥʤΥޥå󥰤ȤȤ˺٥󤵤ޤ
.B yytext

.B yyleng
ŬڤĴޤ(㤨
.B yyleng

.I n
Ȥʤޤ)
㤨С "foobar" Ϳȡʲ
"foobarbar" 񤭤ޤ:
.nf

    %%
    foobar    ECHO; yyless(3);
    [a-z]+    ECHO;

.fi
 0 
.B yyless
ͿȡߤʸΤ٥󤵤ޤ
(㤨
.B BEGIN
Ѥ)˥ʤϤˡѹƤʤȡ̵¥롼פȤʤޤ
.PP
.B yyless
ϥޥǤꡢflex ϥեǤΤ߻ѲǽǤꡢ
̤Υե뤫ϻǽǤ뤳ȤդƲ
.IP -
.B unput(c)
ʸ
.I c
ϥȥ꡼ᤷޤᤷʸϼ˥󤵤ʸˤʤޤ
ΥϸߤΥȡ夲
ƺƥ󤷤ޤ
.nf

    {
    int i;
    /* Copy yytext because unput() trashes yytext */
    char *yycopy = strdup( yytext );
    unput( ')' );
    for ( i = yyleng - 1; i >= 0; --i )
        unput( yycopy[i] );
    unput( '(' );
    free( yycopy );
    }

.fi
.B unput()
ʸϥȥ꡼
.I Ƭ
᤹Τǡʸ᤹ˤϸ˸ä᤹ɬפޤ
.PP
.B unput()
ѻνפŪϡ
.B %pointer
ѻ(ǥե)
.B unput()
ƤӽФȡ
üʸ鳫Ϥ 1 ʸĺ˸äƾ񤵤졢
.I yytext
Ƥ
.I ˲
뤳ȤǤ
(嵭Τ褦)
.B unput()
ƤӽФ
.I yytext
Ƥ¸뤿ˤϡϤ̤ξ˥ԡ뤫
ʤ
.B %array
Ȥ褦˹ۤ뤳ȤǤ(ϤΥޥåˡ)
.PP
Ǹˡ
.B EOF
ᤷϥȥ꡼˥եνޡȤ
ʤȤդƲ
.IP -
.B input()
ʸϥȥ꡼फɤߤޤ
 C Ȥ򿩤٤ޤ:
.nf

    %%
    "/*"        {
                register int c;

                for ( ; ; )
                    {
                    while ( (c = input()) != '*' &&
                            c != EOF )
                        ;    /* eat up text of comment */

                    if ( c == '*' )
                        {
                        while ( (c = input()) == '*' )
                            ;
                        if ( c == '/' )
                            break;    /* found the end */
                        }

                    if ( c == EOF )
                        {
                        error( "EOF in comment" );
                        break;
                        }
                    }
                }

.fi
(ʤ
.B C++
ǥѥ뤵줿ȤϡΥ롼
.B yyinput()
Ȥ̾Τˤʤꡢ
.B C++
ȥ꡼
.I input
̾ͤ뤳Ȥ򤱤ޤ)
.IP -
.B YY_FLUSH_BUFFER
ʤХåեեå夷
˥ʤȡޥå褦Ȥ
Хåե
.B YY_INPUT
ˤƥե뤷ޤ(줿ʤǸ)
Υϡ
ʣϥХåեˤƸҤ
Ū
.B yy_flush_buffer()
ؿ̤ʥǤ
.IP -
.B yyterminate()
 return ʸ˻ȤȤޤ
.B yyterminate()
ϥʤλ"ƽλ" ̣ 0 ƤӽФؿ֤ޤ
ǥեȤǤ
.B yyterminate()
ϥեνãȤˤƤФޤ
.B yyterminate()
ϥޥǤꡢʤȤǤޤ
.SH 줿
.I flex
νϤ
.B lex.yy.c
ȤեǤꡢ롼
.B yylex()
ȡȡΥޥå󥰤˻ѤʣΥơ֥ȡ
ʣ°롼ȥޥʤޤǥեȤǤϡ
.B yylex()
ϼΤ褦ޤ:
.nf

    int yylex()
        {
        ... various definitions and the actions in here ...
        }

.fi
(Ķؿץȥפ򥵥ݡȤƤ硢
"int yylex( void )" Ȥʤޤ)
 "YY_DECL" ޥ뤳ȤˤѹǤޤ
㤨мΤ褦˻Ѥ뤳Ȥޤ:
.nf

    #define YY_DECL float lexscan( a, b ) float a, b;

.fi
ϥ롼̾
.I lexscan
Ȥư֤褦ˤ2 ĤưȤޤ
K&R ץȥפδؿѤƥ롼Фư
Ϳ硢򥻥ߥ(;)ǽλɬפޤ
.PP
.B yylex()
ϸƤФ뤿ӡХϥե
.I yyin
(ǥեȤǤɸ)ȡ򥹥󤷤ޤ
եνˤʤ(ξ 0 ֤ޤ)

.I return
ʸ¹Ԥޤǡ¹Ԥ³ޤ
.PP
ʤեνãȡ
.I yyin
ʥեؤʤ
(ʥեؤϤΥեΥ³ޤ)
.B yyrestart()
ƤФʤ¤ꡢ
³ƤӽФ̤Ǥ
.B yyrestart()

.B FILE *
ݥ(
.B YY_INPUT
ꤷ
.I yyin
ʳΥ򥹥󤹤褦ˤˤ nil ĤǤ)
Ǥ 1 ĤȤꡢΥե뤫ΥΤ
.I yyin
ޤ
ܼŪˡ
.I yyin
򿷤ϥե˳Ƥ뤳Ȥ
.B yyrestar()
Ѥ뤳ȤȤƱǤ;
ԤΥС
.I flex
ȤθߴΤ˻ѲǽǤꡢ
ޤϥեѤ뤳ȤǽǤ

.I yyin
ȤƸƤӽФȤˤꡢߤϥХåեΤƤ뤳Ȥޤ;

.B YY_FLUSH_BUFFER
()ѤɤǤ
.B yyrestart()

.B INITIAL
γϾѹ
.I ʤ
ȤդƲ
(ҤγϾﻲ)
.PP
륢
.I return
ʸ¹Ԥ뤳Ȥˤ
.B yylex()
ߤ᤿硢ʤϺٸƤӽФǽǤꡢ
ξ祹λĤʬƳޤ
.PP
ǥեȤ(ΨΤ)ʤñ
.I getc()
ǤϤʤ֥å꡼ɤԤ
.I yyin
ʸɤߤޤ
ϼˡ
.B YY_INPUT
ޥ뤳ȤˤǤޤ
YY_INPUT ƤӽФ "YY_INPUT(buf,result,max_size)" Ǥ
Υϡ
.I buf
ʸ˺
.I max_size
ʸѰդѿ
.I result
ɤ᤿ʸ⤷ YY_NULL (Unix ƥǤ 0)֤ޤ
ǥեȤ YY_INPUT ϥХեݥ "yyin" ɤߤޤ
.PP
YY_INPUT ΥץǤ(ϥե˳Ǽ):
.nf

    %{
    #define YY_INPUT(buf,result,max_size) \\
        { \\
        int c = getchar(); \\
        result = (c == EOF) ? YY_NULL : (buf[0] = c, 1); \\
        }
    %}

.fi
ˤꡢϽ 1 ٤ 1 ʸĹԤ褦ѹޤ
.PP
ʤ YY_INPUT եνΤ줿硢
ʤ
.B yywrap()
ؿåޤ
.B yywrap()
ؿ()֤硢ؿ³ǤȤ졢
.I yyin
̤ϥեؤ褦ꤷ³Ԥޤ
ؿ(󥼥)֤硢ʤϽλƤӽФ 0 ֤ޤ
ɤξⳫϾѲʤȤդƲ;
Ĥޤ
.B INITIAL
ˤ
.I ޤ
.PP
ȼ
.B yywrap()
ꤷʤ硢
.B %option noyywrap
(ξ祹ʤ
.B yywrap()
 1 ֤Τ褦ưޤ)Ѥ뤫ե饰
.B \-ll
ꤷƥǥեȤΥ롼( 1 ֤ޤ)ѤʤФʤޤ
.PP
եǤϤʤΥХåե饹󤹤뤿 3 ĤΥ롼
ѲǽǤ:
.B yy_scan_string(), yy_scan_bytes(), yy_scan_buffer()

˴ؤʣϥХåե򻲾ȤƲ
.PP
ʤϡʤ
.B ECHO
Ϥ
.I yyout
Х(ǥեȤǤɸϤǤꡢ
̤
.B FILE
ݥ󥿤˳Ƥ뤳ȤǺǤޤ)˽񤭤ޤ
.SH Ͼ
.I flex
ϡŪͭȤʤ롼Τε󶡤ޤ
ѥΥץեå "<sc>" ȤʤäƤ롼ϡ
ʤ "sc" Ȥ̾γϾˤΤͭǤ
㤨С
.nf

    <STRING>[^"]*        { /* eat up the string body ... */
                ...
                }

.fi
ϥʤ "STRING" ϾˤΤͭǤꡢ
.nf

    <INITIAL,STRING,QUOTE>\\.        { /* handle an escape ... */
                ...
                }

.fi
ϸߤγϾ郎
"INITIAL", "STRING", "QUOTE" Τ줫ξΤͭǤ
.PP
ϾϡϤ(Ƭ)ˤơǥȤʤԤ
.B %s
⤷
.B %x
Ϥޤ̾³Ԥˤޤ
Ԥ
.I Ū
Ͼ
Ԥ
.I ¾Ū
Ͼ򡢤줾ޤ
ϾͭˤΤ
.B BEGIN
Ǥ

.B BEGIN
󤬼¹ԤޤǡͿ줿ϾΥ롼ͭǤꡢ
¾γϾΥ롼̵Ǥ
Ͼ郎
.I Ū
ʾ硢Ͼʤ롼ޤͭǤ
Ͼ郎
.I ¾Ū
ʾ硢
Ͼ롼
.I 
ͭǤ
Ʊ¾Ͼ˰¸롼Ȥϡ
.I flex
̤Υ롼ȤΩʥʤ򵭽Ҥޤ
Τᡢ¾ϾѤС"ߥ˥"
(ʬȤʸˡŪ˰ۤʤʬ(㤨Х)Ф륹)
ñ˻Ǥޤ
.PP
ŪϾ¾ŪϾȤޤۣǤʤ顢
ξԤδطɽ򼨤ޤʲΥ롼:
.nf

    %s example
    %%

    <example>foo   do_something();

    bar            something_else();

.fi

.nf

    %x example
    %%

    <example>foo   do_something();

    <INITIAL,example>bar    something_else();

.fi
Ǥ
.B <INITIAL,example>
̵ȡ2 ܤˤ
.I bar
ѥϡϾ郎
.B example
ξ硢ͭȤʤޤ(ʤޥåޤ)
.B <example>

.I bar
ˤĤȡ
.B example
ˤͭȤʤꡢ
.B INITIAL
ǤͭȤʤޤ󡣰ǽǤϤɤξǤͭǤ
ʤʤǽǤ
.B example
Ͼ
.I Ū
.B (%s)
ϾǤ
.PP
üʳϾ
.B <*>
ƤγϾ˥ޥå뤳ȤդƲ
ΤᡢϼΤ褦ˤ񤱤ޤ;
.nf

    %x example
    %%

    <example>foo   do_something();

    <*>bar    something_else();

.fi
.PP
ǥեȥ롼(ޥåʤäʸФƤ
.B ECHO
Ǥ)ϳϾǤͭǤ
ϼΤΤǤ:
.nf

    <*>.|\\n     ECHO;

.fi
.PP
.B BEGIN(0)
ϡϾ̵롼ͭǤ롢ǽξ֤ޤ
ξ֤ϳϾ "INITIAL" ȤƻȤǤ뤿ᡢ
.B BEGIN(INITIAL)

.B BEGIN(0)
Ǥ
(Ͼ̤̾פǤɤǤȤƤޤ)
.PP
.B BEGIN
ϡ롼ƬΥǥȤ줿˸ƤɤǤ
㤨аʲǤϡ
.B yylex()
ƤФ쥰Хѿ
.I enter_special
ξˤϡʤ "SPECIAL" Ͼޤ:
.nf

            int enter_special;

    %x SPECIAL
    %%
            if ( enter_special )
                BEGIN(SPECIAL);

    <SPECIAL>blahblahblah
    ...more rules follow...

.fi
.PP
Ͼ뤿ˡ
"123.456" Τ褦ʸ 2 ̤ΰۤʤä򤹤륹ʤ򼨤ޤ
ǥեȤǤϤϡ
 "123" ȥɥå ('.')  "456"  3 ȡ˿ޤ
ʸ "expect-floats" ʸ󤬤硢
ñΥȡǤȤ졢ư 123.456 Ȥޤ:
.nf

    %{
    #include <math.h>
    %}
    %s expect

    %%
    expect-floats        BEGIN(expect);

    <expect>[0-9]+"."[0-9]+      {
                printf( "found a float, = %f\\n",
                        atof( yytext ) );
                }
    <expect>\\n           {
                /* that's the end of the line, so
                 * we need another "expect-number"
                 * before we'll recognize any more
                 * numbers
                 */
                BEGIN(INITIAL);
                }

    [0-9]+      {
                printf( "found an integer, = %d\\n",
                        atoi( yytext ) );
                }

    "."         printf( "found a dot\\n" );

.fi
ϡC ΥȤ(ƼΤƤ)ǡ
ߤϹԤ륹ʤǤ
.nf

    %x comment
    %%
            int line_num = 1;

    "/*"         BEGIN(comment);

    <comment>[^*\\n]*        /* eat anything that's not a '*' */
    <comment>"*"+[^*/\\n]*   /* eat up '*'s not followed by '/'s */
    <comment>\\n             ++line_num;
    <comment>"*"+"/"        BEGIN(INITIAL);

.fi
Υʤϳƥ롼ǲǽʺΥƥȤ˥ޥå褦Ȥ硢
äȤ꤬ޤ
Ūˤϡ®ʥʤ򵭽Ҥ硢
ƥ롼ǺΥޥå褦Ȥ뤳ȤǤޤ
.PP
Ͼ̾ϼºݤˤͤǤꡢǼ뤳Ȥ뤳ȤդƲ
Τᡢ嵭ϰʲΤ褦˳ĥǤޤ:
.nf

    %x comment foo
    %%
            int line_num = 1;
            int comment_caller;

    "/*"         {
                 comment_caller = INITIAL;
                 BEGIN(comment);
                 }

    ...

    <foo>"/*"    {
                 comment_caller = foo;
                 BEGIN(comment);
                 }

    <comment>[^*\\n]*        /* eat anything that's not a '*' */
    <comment>"*"+[^*/\\n]*   /* eat up '*'s not followed by '/'s */
    <comment>\\n             ++line_num;
    <comment>"*"+"/"        BEGIN(comment_caller);

.fi
ˡߤγϾͤǤޥ
.B YY_START
ˤƥǤޤ
㤨С嵭
.I comment_caller
ؤϼΤ褦˵ҤǤޤ
.nf

    comment_caller = YY_START;

.fi
flex 
.B YYSTATE

.B YY_START
ΥꥢȤ󶡤ޤ
(AT&T 
.I lex
ѤƤޤ)
.PP
Ͼȼ֤̾ʤȤդƲ;
%s  %x ˤ̾ΰ #define ƱǤ
.PP
Ǹˡ¾ŪϾѤ롢
Ÿ줿ץ󥹤ޤ(ĹʸΥåϴޤߤޤ)
C ΥʸؤΥޥåˡ򼨤ޤ:
.nf

    %x str

    %%
            char string_buf[MAX_STR_CONST];
            char *string_buf_ptr;


    \\"      string_buf_ptr = string_buf; BEGIN(str);

    <str>\\"        { /* saw closing quote - all done */
            BEGIN(INITIAL);
            *string_buf_ptr = '\\0';
            /* return string constant token type and
             * value to parser
             */
            }

    <str>\\n        {
            /* error - unterminated string constant */
            /* generate error message */
            }

    <str>\\\\[0-7]{1,3} {
            /* octal escape sequence */
            int result;

            (void) sscanf( yytext + 1, "%o", &result );

            if ( result > 0xff )
                    /* error, constant is out-of-bounds */

            *string_buf_ptr++ = result;
            }

    <str>\\\\[0-9]+ {
            /* generate error - bad escape sequence; something
             * like '\\48' or '\\0777777'
             */
            }

    <str>\\\\n  *string_buf_ptr++ = '\\n';
    <str>\\\\t  *string_buf_ptr++ = '\\t';
    <str>\\\\r  *string_buf_ptr++ = '\\r';
    <str>\\\\b  *string_buf_ptr++ = '\\b';
    <str>\\\\f  *string_buf_ptr++ = '\\f';

    <str>\\\\(.|\\n)  *string_buf_ptr++ = yytext[1];

    <str>[^\\\\\\n\\"]+        {
            char *yptr = yytext;

            while ( *yptr )
                    *string_buf_ptr++ = *yptr++;
            }

.fi
.PP
嵭Τ褦ƱγϾƤΥ롼
Ͼ񤫤ͤФʤʤȤ¿Ǥ
flex Ϥñˤ뤿ᳫϾ
.I 
Ƴޤ
Ͼ凉פϼΤ褦˻Ϥޤޤ:
.nf

    <SCs>{

.fi

.I SCs
 1 İʾγϾΥꥹȤǤ
Ͼ凉Ǥϡ
ǽ
.I '{'
˥ޥåޤǤ
.I '}'
ˤơƤΥ롼ϼưŪ
.I <SCs>
Υץեåդޤ
Τᡢ㤨
.nf

    <ESC>{
        "\\\\n"   return '\\n';
        "\\\\r"   return '\\r';
        "\\\\f"   return '\\f';
        "\\\\0"   return '\\0';
    }

.fi
ϼΤΤǤ:
.nf

    <ESC>"\\\\n"  return '\\n';
    <ESC>"\\\\r"  return '\\r';
    <ESC>"\\\\f"  return '\\f';
    <ESC>"\\\\0"  return '\\0';

.fi
Ͼ凉פϥͥȤ뤳Ȥޤ
.PP
ϾΥå椹뤿 3 ĤΥ롼ѲǽǤ:
.TP
.B void yy_push_state(int new_state)
ߤγϾ򳫻Ͼ凉åƬ˥ץå夷
.B BEGIN new_state
ѤΤ褦
.I new_state
ڤؤޤ
(Ͼ̾ͤǤ⤢뤳ȤפФƲ)
.TP
.B void yy_pop_state()
åƬݥåפ
.B BEGIN
ѤƤγϾڤؤޤ
.TP
.B int yy_top_state()
åƤѹˡåƬ֤ޤ
.PP
Ͼ凉åưŪ礭ʤꡢ
ޤȤ߹߻Υ¤Ϥޤ
Ȥڤȡץ¹Ԥߤޤ
.PP
Ͼ凉åѤ뤿ˤϡʤ
.B %option stack
ǥ쥯ƥ֤򥤥󥯥롼ɤɬפޤ
(ץ򻲾ȤƲ)
.SH ʣϥХåե
ʤˤäƤ(ե "include" 򥵥ݡȤ)
ʣϥȥ꡼򰷤ɬפޤ
.I flex
ʤǤ礭ʥХåե󥰤Ԥᡢ
󥳥ƥȤ˱ƶ
.B YY_INPUT
ñ˽񤭴ǤϼϤɤɤޤΤǤޤ
.B YY_INPUT
ƤФΤϥʤХåեνãǤΤǡ
㤨 "include" Τ褦ϸڤؤɬפΤʸ򥹥󤷤Ǥ
Ĺ֤񤹾礬ޤ
.PP
ͤ褹뤿ᡢ
.I flex
ʣϥХåեڤؤ뵡󶡤ޤ
ϥХåեϼΤ褦ޤ:
.nf

    YY_BUFFER_STATE yy_create_buffer( FILE *file, int size )

.fi

.I FILE
ݥ󥿤 size ꡢͿ file ˴Ϣ
.I size
ʸݻ˽ʬʥХåեޤ
(路ˤ size ˤ
.B YY_BUF_SIZE
ѤƲ)
ϡ̤Υ롼()Ϥ
.B YY_BUFFER_STATE
ϥɥ֤ޤ
.B YY_BUFFER_STATE
Υפ
.B struct yy_buffer_state
¤ΤؤΥݥ󥿤Ǥ뤿ᡢ
Τ YY_BUFFER_STATE ѿ
.B ((YY_BUFFER_STATE) 0)
Ƚ뤳Ȥ衢
ʤǤϤʤեˤ
ϥХåե뤿ˤι¤Τ򻲾Ȥ뤳Ȥޤ
.B yy_create_buffer
ƤӽФˤ
.I FILE
ݥ󥿤
.B YY_INPUT
鸫
.I yyin
ͤƱ褦ˤѤ뤳ȤդƲ;
.B YY_INPUT

.I yyin
Ȥʤ褦ˤ뤳Ȥˤꡢ
.B yy_create_buffer
Фư˥˥
.I FILE
ݥ󥿤Ϥޤ
󤹤Хåե򤹤뤿ˤϼΤ褦ˤޤ:
.nf

    void yy_switch_to_buffer( YY_BUFFER_STATE new_buffer )

.fi
ϥʤϥХåեڤؤ
ȡ
.I new_buffer
褦ˤʤޤ
ʥե򥪡ץ󤷤
.I yyin
ؤΤǤϤʤ³뤿 yywrap() 
.B yy_switch_to_buffer()
Ѥ뤳Ȥ뤳ȤդƲ
ޤ
.B yy_switch_to_buffer()
ޤ
.B yywrap()
ˤϸڤؤϳϾѹ
.I ʤ
ȤˤդƲ
.nf

    void yy_delete_buffer( YY_BUFFER_STATE buffer )

.fi
ϥХåե˴ϢŤ줿ȥ졼ִ׵˻Ѥޤ(
.B buffer
ϥ˥Ǥ⹽ޤ󤬤ξ礳Υ롼ϲ⤷ޤ)
ߤΥХåեƤ򥯥ꥢˤϼΤ褦ˤޤ:
.nf

    void yy_flush_buffer( YY_BUFFER_STATE buffer )

.fi
δؿϥХåեƤΤƤ뤿ᡢ
˥ʤΥХåեȥȡΥޥåԤ硢
ʤϤޤ
.B YY_INPUT
ѤƤΥХåեե뤷ޤ
.PP
.B yy_new_buffer()

.B yy_create_buffer()
ΥꥢǤꡢưŪ֥Ȥ˲Τ˻Ѥ C++ 
.I new

.I delete
ȤθߴΤ󶡤Ƥޤ
.PP
Ǹ
.B YY_CURRENT_BUFFER
ޥϡߤΥХåեФ
.B YY_BUFFER_STATE
ϥɥ֤ޤ
.PP
εǽѤƥ󥯥롼ɥեŸ륹ʤεǤ(
.B <<EOF>>
ǽϸҤޤ):
.nf

    /* the "incl" state is used for picking up the name
     * of an include file
     */
    %x incl

    %{
    #define MAX_INCLUDE_DEPTH 10
    YY_BUFFER_STATE include_stack[MAX_INCLUDE_DEPTH];
    int include_stack_ptr = 0;
    %}

    %%
    include             BEGIN(incl);

    [a-z]+              ECHO;
    [^a-z\\n]*\\n?        ECHO;

    <incl>[ \\t]*      /* eat the whitespace */
    <incl>[^ \\t\\n]+   { /* got the include file name */
            if ( include_stack_ptr >= MAX_INCLUDE_DEPTH )
                {
                fprintf( stderr, "Includes nested too deeply" );
                exit( 1 );
                }

            include_stack[include_stack_ptr++] =
                YY_CURRENT_BUFFER;

            yyin = fopen( yytext, "r" );

            if ( ! yyin )
                error( ... );

            yy_switch_to_buffer(
                yy_create_buffer( yyin, YY_BUF_SIZE ) );

            BEGIN(INITIAL);
            }

    <<EOF>> {
            if ( --include_stack_ptr < 0 )
                {
                yyterminate();
                }

            else
                {
                yy_delete_buffer( YY_CURRENT_BUFFER );
                yy_switch_to_buffer(
                     include_stack[include_stack_ptr] );
                }
            }

.fi
եǤϤʤʸ򥹥󤹤뤿
ϥХåեꤹ뤿 3 ĤΥ롼ѲǽǤ
ʸ򥹥󤹤뿷ϥХåեб
.B YY_BUFFER_STATE
ϥɥ(λˤ
.B yy_delete_buffer()
ˤƾõޤ)֤ޤХåեڤؤˤ
.B yy_switch_to_buffer()
Ѥ
.B yylex()
θƤӽФˤϤʸ򥹥󳫻Ϥޤ
.TP
.B yy_scan_string(const char *str)
NUL ߥ͡Ȥ줿ʸ򥹥󤷤ޤ
.TP
.B yy_scan_bytes(const char *bytes, int len)
.I len
Х (NUL ޤޤ뤫Τޤ)
.I bytes
饹󤷤ޤ
.PP
ɤδؿʸ⤷ϥХ
.I ԡ
Ƥ饹󤷤ޤ(
.B yylex()
ϥ󤹤ХåեƤѹ뤿ᡢ줬˾ޤΤǤ)
ԡ򤱤뤿ˤϼΤ褦ˤޤ:
.TP
.B yy_scan_buffer(char *base, yy_size_t size)
Хåե
.I base

.I size
ХȤĹ򥹥󤷤ޤǸ 2 ХȤ
.B YY_END_OF_BUFFER_CHAR
(ASCII NUL)
Ǥ
.I ɬפޤ
κǸ 2 ХȤϥ󤵤ޤ;
Τ᥹Ƥ
.B base[0]

.B base[size-2]
ޤǤξüޤߤޤ
.IP
ͤˤʤ褦
.I base
ꤷʤä(ĤޤǸ 2 Ĥ
.B YY_END_OF_BUFFER_CHAR
ХȤ˺줿)
.B yy_scan_buffer()
ϿХåեΤǤϤʤ˥ݥ󥿤֤ޤ
.IP

.B yy_size_t
Ǥꡢ
Хåե礭ȿǤ򤳤η˥㥹Ȥ뤳Ȥޤ
.SH եνΥ롼
̥롼 "<<EOF>>" ϡ
եνλ⤷
yywrap() 󥼥(ʤե뤬̵Ȥɽ)λ
Ԥ٤ɽޤ
ϰʲ 4 ĤΤΤ줫ǽɬפޤ
.IP -
.I yyin
˿եƤ(ΥС flex Ǥϡ
Ƹ̤ʥ
.B YY_NEW_FILE
ƤӽФɬפޤ;
ǤפǤ);
.IP -
.I return
ʸ¹Ԥ;
.IP -
̤
.B yyterminate()
¹Ԥ;
.IP -
.B yy_switch_to_buffer()
ѤƿʥХåեڤؤ
(嵭Ǽ̤)
.PP
<<EOF>> 롼¾Υѥȶ˻ѤƤϤʤޤ;
¾ΥѥϳϾΥꥹȤȤˤ뤫Ǥ
ʤ <<EOF>> 롼뤬Ϳ줿硢
<<EOF>> ޤäƤʤ
.I Ƥ
ϾŬѤޤ
<<EOF>> 롼ǽγϾ˻ꤹ뤿ˤϼΤ褦ˤƲ
.nf

    <INITIAL><<EOF>>

.fi
.PP
Υ롼ĤƤʤȤޤǤ
㤨:
.nf

    %x quote
    %%

    ...other rules for dealing with quotes...

    <quote><<EOF>>   {
             error( "unterminated quote" );
             yyterminate();
             }
    <<EOF>>  {
             if ( *++filelist )
                 yyin = fopen( *filelist, "r" );
             else
                yyterminate();
             }

.fi
.SH ¿ʥޥ
ޥ
.B YY_USER_ACTION
ˤϥޥå롼륢äƾ˹ԤǤޤ
㤨Сyytext ʸѴ롼Ƥ֤褦 #define ޤ
.B YY_USER_ACTION
ưˤϡѿ
.I yy_act
ϥޥå롼ֹͿޤ(롼 1 ֤ޤ)
ƥ롼뤬ޥå٤ΤꤿƲ
ʲ˻ųݤ򼨤ޤ:
.nf

    #define YY_USER_ACTION ++ctr[yy_act]

.fi

.I ctr
Ǥꡢ줾Υ롼뤬ޥå׿ޤ
ޥ
.B YY_NUM_RULES
ϥ롼ɽ(
.B \-s
ȤäǤǥեȥ롼ޤߤޤ)

.I ctr
ϼΤ褦ˤʤޤ:
.nf

    int ctr[YY_NUM_RULES];

.fi
.PP
ޥ
.B YY_USER_INIT
ˤϺǽΥ˾˹ԤǤޤ
(ʤ˹Ԥޤ)
㤨Хǡɽɤ߹ꡢե򥪡ץ󤹤뤿˻ѤǤޤ
.PP
ޥ
.B yy_set_interactive(is_interactive)
ϸߤΥХåե
.I Ū
ȸ蘆Ƥ뤫ݤ椹뤿˻Ѥޤ
ŪʥХåեν٤ʤޤ
ʤϸŪǤХåեե뤹ΤԤĤȤ˵
򤱤뤿ˤϻꤷʤФʤޤ(ʲ
.B \-I
.B %option interactive
ե饰˴ؤ򻲾ȤƲ)
ޥư󥼥ꤹȥХåեŪˤʤꡢ
ꤹŪˤʤޤ
ΥޥλѤ
.B %option interactive ,
.B %option always-interactive ,
.B %option never-interactive
ͥ褷ޤ(ץ򻲾ȤƲ)
Хåե򥹥󤷤ŪǤ(⤷ϤǤʤ)ȽǤˡ
.B yy_set_interactive()
ưƲ
.PP
ޥ
.B yy_set_bol(at_bol)
ϸߤΥХåեˤ뼡ΥȡФޥåΤΥ
ƬϤޤ뤫ݤ椷ޤ
󥼥Υޥϡ'^' դ롼ͭˤޤ
Υޥ '^' դ롼̵ˤޤ
.PP
ߤΥХåե饹󤵤줿Υȡͭ '^' 롼Ļ
ޥ
.B YY_AT_BOL()
Ͽ֤ޤ
Ǥʤϵ֤ޤ
.PP
줿ʤǤϡƤΥ礭ʰĤ switch ʸ
졢
.B YY_BREAK
ʬƤޤ
.B YY_BREAK
ϺǽǤǥեȤǤϤ줾Υ롼Υ
ʬ뤿ñʤ "break" Ǥ
.B YY_BREAK
뤳Ȥˤꡢ㤨 C++ 桼
#define YY_BREAK 򲿤⤷ʤ褦
(ƤΥ롼뤬 "break"  "return" ǽ褦
դʤФʤޤ!)
롼Υ "return" ǽ뤳Ȥˤ
.B YY_BREAK
ǤʤȤ˵롢
ãǤʤʸȤٹ򤱤뤳Ȥޤ
.SH 桼Ѳǽ
Ǥϥ桼롼ΥʬǻѲǽͤޤȤޤ
.IP -
.B char *yytext
ȡΥƥȤݻƤޤƤѹƤ⹽ޤ󤬡
Ĺ򿭤ФƤϤޤ(ʸɲäƤϤʤ)
.IP
ʤεҤκǽʬ̤ʻؼǤ
.B %array
񤫤ƤȤ
.B yytext

.B char yytext[YYLMAX]
ޤ
.B YYLMAX
ϥޥǡǥեȤ (¿ξ8KB) ѹˤ
ǽʬǺǽǤ
.B %array
ȤȤ餫٤ʤˤʤޤ
.B yytext
ͤ
.I input()

.I unput()
θƤӽФǤ˲ʤʤޤ
.B yytext
ʸݥ󥿤Ǥ硢
δؿƤӽФ
.B yytext
˲ǽޤ
.B %array
оΤʻ
.B %pointer
ǥեȤǤ
.IP
C++ Υʥ饹 (ץ
.B \-+
) Ȥˤ
.B %array
ϻȤޤ
.IP -
.B int yyleng
ȡĹݻƤޤ
.IP -
.B FILE *yyin
ϥǥեȤ
.I flex
ɤեǤ뤳ȤϲǽǤ
Ϥ EOF ãǤΤߺϰ̣ޤ
ѹͽ۳η̤⤿餷ޤ
ȤΤ
.I flex
ϤХåե󥰤Ƥ뤫Ǥ;
Τ褦ʾˤϡľܺ
.B yyrestart()
ȤäƲ
եνǥ󤬽λˤ
.I yyin
򿷤ϥե˳ơ
ƤӥʤƤӽФƥ³뤳Ȥޤ
.IP -
.B void yyrestart( FILE *new_file )
Ƥ֤Ȥ
.I yyin
ϥեؤ褦˽ޤեؤѹ
˹Ԥޤ (ޤǤ˥Хåեɤ߹ޤƤϤϼޤ)
.I yyin
Ȥ
.B yyrestart()
Ƥ֤ȡߤϥХåեΤƤƱϥե
³뤳ȤդƲ
.IP -
.B FILE *yyout

.B ECHO
󤬹ԤоݤΥեǤ
桼Ƴ뤳Ȥޤ
.IP -
.B YY_CURRENT_BUFFER
ȥХåե
.B YY_BUFFER_STATE
ϥɥ֤ޤ
.IP -
.B YY_START
ߤγϾб֤ͤޤ
³Ƥͤ
.B BEGIN
ȶ˻ȤȤǡʤ򤽤γϾ᤹Ȥޤ
.SH YACC ȤΥ󥿥ե
.I flex
μʻˡΰĤϡ
.I yacc
ѡͥ졼ȶ˻Ѥ뤳ȤǤ
.I yacc
ѡ
.B yylex()
ȸ̾Υ롼ƤӡϥȡդΤȤƤޤ
Υ롼ϡΥȡη֤
Ϣͤ򥰥Х
.B yylval
˳ǼΤȤƤޤ
.I flex

.I yacc
ȶ˻Ȥˤϡ
.I yacc

.B \-d
ץꤷơ
.I yacc
Ϥ˸Ƥ
.B %tokens
ޤ
.B y.tab.h
եޤ
Υե
.I flex
ʤ˥󥯥롼ɤޤ
㤨ХȡΰĤ "TOK_NUMBER" Ǥ硢
ʤΰʬϼΤ褦ˤʤäƤޤ:
.nf

    %{
    #include "y.tab.h"
    %}

    %%

    [0-9]+        yylval = atoi( yytext ); return TOK_NUMBER;

.fi
.SH ץ
.I flex
ˤϰʲΤ褦ʥץ󤬤ޤ:
.TP
.B \-b
Хåå׾
.I lex.backup
˽Ϥޤ
ΥեˤϡʤΥХåå(backing-up)ɬפȤ֤
бʸΰꥹȤޤ
롼ɲä뤳ȤǥХåå׾֤
ǤޤХåå׾֤
.I 
졢
.B \-Cf
ޤ
.B \-CF
ꤹȡ줿ʤμ¹®٤夷ޤ(
.B \-p
ե饰򸫤Ʋ)
ʤ򤮤꤮ޤǺŬ褦ȤƤ桼Τߤ
Υץ˴طޤ
(ҤǽϢ򸫤Ʋ)
.TP
.B \-c
⤷ޤPOSIX ߴΤѰդƤޤ
.TP
.B \-d
줿ʤ
.I ǥХå
⡼ɤǼ¹Ԥޤ
.B yy_flex_debug
󥼥ξ(ǥե)
ѥǧ뤿ӤˡʤϼΤ褦ʥå
.I ɸ२顼
ؽϤޤ
.nf

    --accepting rule at line 53 ("the matched text")

.fi
ֹϥʤƤե (flexͿ줿ե)
ǤΥ롼ΰ֤Ǥ
ʤХååפȤǥեȥ롼줿Ȥ
ϥХåեκǸãȤ (뤤ϡNULãȤ;
ʤˤϡĤζ̤ϤĤޤ) եκǸã
ȤˤåϤޤ
.TP
.B \-f
.I ®ʥ
ꤷޤ
ơ֥밵̤ϹԤ줺ɸϤХѥޤ
η륹ʤ礭ʤޤ®ʤΤˤʤޤ
Υץ
.B \-Cfr
ƱǤ (ʲ򻲾)
.TP
.B \-h
.I flex
Υץ󤫤ʤ "إ" 
.I ɸ
˽񤭽Фλޤ
.B \-?

.B \-\-help
Ȥ
.B \-h
ƱǤ
.TP
.B \-i
.I ʸʸ̤ʤ
ʤޤ
.I flex
ϥѥͿʸʸǤ뤫ʸǤ뤫϶̤줺
ʤϤʸʸʸ˴طʤޥåޤ
ޥåƥ
.I yytext
Ǥϻʸʸ¸ޤ (ʸʸѴꤷޤ)
.TP
.B \-l
AT&T 
.I lex
μФƺ¤θߴޤ
.I 
ߴ̣ޤ
ΥץѤǽ礭ʱƶޤ
Υץϡ
.B \-+, \-f, \-F, \-Cf, \-CF
Ʊ˻ѤǤޤ󡣾ܤϡ
Ҥ "Lex  POSIX Ȥߴ" 
ޤΥץѤȡ
.B YY_FLEX_LEX_COMPAT
줿ʤ̾ #define ޤ
.TP
.B \-n
⤷ޤPOSIX ߴΤˤѰդ줿ץǤ
.TP
.B \-p
ǽɸ२顼Ϥ˽Ϥޤ
.I flex
ϥեεҤΤ
륹ʤǽ㲼οʸȤʤʬˤĤơ
Ȥޤ
ץ2ꤹȡ٤ǽ㲼ˤĤƤ
ȤϤޤ
.IP
.B REJECT

.B %option yylineno
Ĺʸ̮(/ХǸ)¿ʤǽؤΰƶޤ;
.I yymore()
λѡ
.B ^
ڥ졼
.B \-I
ե饰Ͼǽΰƶޤ
.TP
.B \-s
.I ǥեȥ롼
(ޥåʤʤϤ
.I ɸ
˽Ϥ)
ޤ롼˥ޥåʤϤɽ줿Ȥʤ
顼ǰ۾ｪλޤ
ʤΥ롼Ȥȴ̵ǧͭǤ
.TP
.B \-t
.B lex.yy.c
ǤϤʤɸϤ˥ʤ񤭽Фޤ
.TP
.B \-v
륹ʤħ
.I ɸ२顼
˽Ϥ褦
.I flex
˻ؼޤ
ۤȤɤħ̾
.I flex
桼ˤϰ̣ޤ󤬡ǽιԤ
.I flex
ΥСɽ(
.B \-V
ɽƱǤ)ιԤϥǥեȤޤॹΥե饰Ǥ
.TP
.B \-w
ٹåޤ
.TP
.B \-B
.I Ū
ʥ (ʲ
.B \-I
ι򻲾) ǤϤʤ
.I ХåŪ
ʥʤ褦
.I flex
˻ؼޤ
̾
.B \-B
ѤΤϡʤŪ˻ѤʤȤ
.I ʬäƤ
Ǥꡢ
.I Ǥ
ǽɵᤷǤ
礭ǽɵ᤹ˤϡ
.B \-Cf
⤷
.B \-CF
ץѤ٤Ǥ()
.B \-B
ưŪꤷޤ
.TP
.B \-F
.ul
®
ʥơ֥ɽȤ(ɸϤϥХѥ)Ȥꤷޤ
ɽϡơ֥ɽ
.B (-f)
ȤۤƱ餤®ǡ
ΥѥФƤϤʤ꾮 (ФƤ礭)
ʤޤ
̾Τ褦ˡѥȤ "keywords" Ȥб
 "identifier" 롼뤫ʤ:
.nf

    "case"    return TOK_CASE;
    "switch"  return TOK_SWITCH;
    ...
    "default" return TOK_DEFAULT;
    [a-z]+    return TOK_ID;

.fi
ξ硢ơ֥ɽѤɤǤ
⤷ "identifier" 롼뤫Τɽ졢
ɤΤ뤿˥ϥåɽѤϡ
.B -F
ѤɤǤ
.IP
Υץ
.B \-CFr
Ǥ (ʲ򻲾)

.B \-+
ץȤƱ˻Ǥޤ
.TP
.B \-I
.I flex

.I Ū
ʥʤ褦˻ؼޤ
Ūʥʤϡ
ɤߤ뤳Ȥˤޥåȡ󤬴˷ޤΤɤߤޤ
ߤΥȡ󤬴餫ʾǤɤߤˡϡ
ɬ׻Τɤߤˡ꾯®Ǥ
ɤߤˡǤǽƶޤ;
㤨Х桼ԤϤ硢
.I ̤
ȡϤޤǤϲԤȤǧޤ
糵ξ硢ιΤϤ뤳Ȥˤʤޤ
.IP
.I flex
ΥʤΥǥեȤ
.I Ū
Ǥꡢ㳰
.B \-Cf

.B \-CF
Ȥäơ֥밵̥ץ()ѻǤ
ǽɵˤϤΥץѤƤ٤ǤΤǡ
ΥץѤƤʤˤϡ
.I flex
ϼ¹Իǽ򾯤ˤľŪŪʿ񤤤äƤΤȤޤ
.B \-I
ץ
.B \-Cf

.B \-CF
ȶ
.I ѤǤʤ
ȤˤդƲ
ºݤϤΥץפǤ;
硢ǥեȤͭˤʤäƤޤ
.IP
.B isatty()
ʤϤФƵ֤硢
.B \-I
ꤵƤǤ⡢flex ϥХå⡼ɤޤ
ʤˤäƤå⡼ɤˤϡ
.B %option always-interactive
(ҤΥץ򻲾) Ѥޤ
.IP
ʤŪ
.I ̵
褦˶ˤ
.B \-B
()Ѥޤ
.TP
.B \-L
.I flex

.B #line
ǥ쥯ƥ֤
.B lex.yy.c
ʤ褦˻ؼޤ
ǥեȤǤϤ #line ǥ쥯ƥ֤Τǡ
ˤ륨顼åϡꥸʥ
.I flex
ϥե(
顼ϥեΥɤ˵)⤷
ե
.B lex.yy.c
(
.I flex
θ -- ʲŻҥ᡼륢ɥ쥹𤷤Ʋ)
ˤ֤Ϳޤ
.TP
.B \-T
.I flex

.I ȥ졼
⡼ɤǼ¹Ԥޤ
ϤηȤη̤ȤƽϤ/ͭ
ȥޥȥ˴ؤ
.I ɸ२顼
¿̤ΥåϤޤ
Υץϼ
.I flex
ƥʥ󥹤뤿˻Ȥޤ
.TP
.B \-V
Сֹ
.I ɸ
˽Ϥƽλޤ
.B \-\-version

.B \-V
ƱǤ
.TP
.B \-7
7 ӥåȤΥʤޤ
ʤϤ 7 ӥåȤʸΤߤѤ뤳Ȥ̣ޤ
.B \-7
ꤹϡ
.B \-8
ץ()ꤷơ֥ȾʬޤǾʤꤦ뤳ȤǤ
ϡϤ 8 ӥåʸޤޤƤˡ
ʤϥ󥰤⤷ϥå夹뤳ȤǤ
.IP
ʤ顢
.B \-Cf

.B \-CF
Ȥäơ֥밵̥ץѻˤϥơ֥밵̤θ̤Ͼʤ
ܿ㲼뤳ȤդƲ
.I flex
ΥǥեȤưǤϡ
.B \-Cf

.B \-CF,
ꤷʤ¤ 8 ӥåȥʤޤ
ˤϡ
ʤΥȤ 8 ӥåȥʤ褦
(USA ʳΥȤǤɤޤ)Ƥʤˤϡ
7 ӥåȥʤޤ
flex  7 ӥåȤ⤷ 8 ӥåȤΤΥʤΤ
ΤꤿˤϡҤ
.B \-v
νϤΥե饰Ĵ٤Ʋ
.IP
.B \-Cfe
⤷
.B \-CFe
(Υơ֥밵̥ץ󤪤饹ϸ)
ѤƤ⡢flex ϥǥեȤ 8 ӥåȥʤ뤳Ȥ
դƲ
ʤʤ顢 8 ӥåȥơ֥ 7 ӥåȥơ֥٤Ƥ
ƹˤϤʤʤǤ
.TP
.B \-8
8 ӥåȤΥʤ褦
.I flex
˻ؼޤʤ 8 ӥåʸᤷޤ
̥ץ
.B \-Cf

.B \-CF
ѻˤΤɬפǤ
ʤʤ flex ϥǥեȤǤ 8 ӥåȥʤ뤫Ǥ
.IP
flex Υǥեư 7 ӥåȤ 8 ӥåȥʤ
ȥ졼ɥդ˴ؤƤϡ嵭
.B \-7
ε򸫤Ʋ
.TP
.B \-+
C++ Υʥ饹ޤ
ܤ C++ ʤǸҤޤ
.TP
.B \-C[aefFmr]
ơ֥밵̤٤ȡ
ŪˤϾʤȹ®ʥʤȤΥȥ졼ɥդꤷޤ
.IP
.B \-Ca
("饤")
륹ʤΥơ֥ϡ
ꥢӷ׻Τ˥饤󤵤뤿ᡢ礭ʤΤˤʤޤ
RISC ƥǤϥ󥰥ɤΥեå
硼ȥɤȤä꾮礭ΤΤФΤΨŪǤ
ˤäƤϥʤΥơ֥륵̾ 2ܤˤʤ뤳Ȥ⤢ޤ
.IP
.B \-Ce
.I 饹
(Ʊλ°ʸå)ۤޤ
(㤨С
.I flex
˿Τʸ饹 "[0-9]" Τߤξ硢
 '0', '1', ..., '9' Ʊ饹ˤʤޤ)
¿ξ硢饹Ѥ뤳ȤǺǽŪʥơ֥/
֥ȥեΥŪ(ʿѤ 1/2-1/5)˸餹Ȥޤ
ޤκݤǽȤ㤯ޤޤ
( 1ʸ󤹤뤴Ȥ 1󸡺ԤǤ)
.IP
.B \-Cf
.I (full)
ʥơ֥뤳Ȥؼޤ -
.I flex
ϡ̤ξ֤˴ؤܴؿ򤦤ޤѤȤ
ơ֥밵̼ˡѤޤ
.IP
.B \-CF
̤ι®ɽ(
.B \-F
ե饰ˤƵ)Ѥ뤳Ȥꤷޤ
Υץ
.B \-+
Ʊ˻ѤǤޤ
.IP
.B \-Cm
.I flex

.I ᥿饹
ۤ褦ؼޤ
᥿饹ϰ˻Ȥ뤳Ȥ¿饹
(饹ȤƤʤȤˤʸ) νǤ
̥ơ֥ȤäƤȤ
᥿饹¿ξˤʤθŪ⤿餷ޤ
ǽ˱ƶޤ
(1-2 ξƥȤ 1 󸡺󤷤ʸȤ˹Ԥޤ)
.IP
.B \-Cr
줿ʤϤФƤɸϥ饤֥(ɸ)
.I Хѥ
ޤ
ʤϡ
.B fread()

.B getc()
ǤϤʤ
.B read()
ƥॳѤޤ
ǽ̤ϥƥ˰¸ޤ
ץ
.B \-Cf
⤷
.B \-CF
ѤƤʤˤϡ
̤ˤΥץǽ򤢤ޤޤ
.B \-Cr
ꤹȡ㤨ХʤꤹɸϤѤ
.I yyin
ɤ߼̯ưȤʤޤ
(ɸϤϥХåե˰ɤ߹Τ򡢥ʤɤޤ)
.IP
.B \-Cr

.B YY_INPUT
̣ޤ
(Ҥ줿ʤ򻲾)
ʤθƽФäɸϤȤä
.I yyin
ɤߤƤȤˤϡͽ۳ο񤤤򤹤뤳Ȥޤ
.IP
.B \-C
ΤߤꤷȤˤϡʤϥơ֥밵̤ϹԤޤ
饹᥿饹Ȥޤ
.IP
ץ
.B \-Cf

.B \-CF
ϥץ
.B \-Cm
Ʊ˻ꤷƤ̣ʤޤ -
ʤʤ顢ơ֥밵̤ԤʤȤ᥿饹
ϸʤǤ
ʳΥץϼͳȤ߹碌뤳Ȥޤ
.IP
ǥեȤ
.B \-Cem
ǤΤȤ
.I flex
饹ȥ᥿饹ޤ
ϺǤ⤤ơ֥밵̤Ԥޤ
ơ֥륵礭ȼ¹Ԥι®ϥȥ졼ɥդδطˤꡢ
̤
.nf

    ٤ 
          -Cem
          -Cm
          -Ce
          -C
          -C{f,F}e
          -C{f,F}
          -C{f,F}a
    ® 礭

.fi
Ȥʤޤ
ơ֥Υʤ̾⥳ѥ®Ǥ뤿ᡢ
̾γȯϺΰ̤ԤǤ礦
.IP
ʤΥʤǤϡ
.B \-Cfe
®٤礭ɤХ󥹤Ǥ
.TP
.B \-ooutput
.B lex.yy.c
ǤϤʤե
.B output
˥ʤ񤯤褦 flex ˻ؼޤ
.B \-o

.B \-t
ץȤ߹碌ȡ
ʤ
.I ɸ
˽񤫤ޤ
.B #line
ǥ쥯ƥ(
.B \\-L
ˤƾ)ϥե
.B output
򻲾Ȥޤ
.TP
.B \-Pprefix
.I flex
λȤǥեȤΥץեå
.I "yy"

.I prefix
ȤޤϥХѿȥե̾˱ƶޤ
㤨
.B \-Pfoo
Ȥȡ
.B yytext
̾
.B footext
Ȥʤޤ
ޤǥեȤνϥե̾
.B lex.yy.c

.B lex.foo.c
Ѥޤ
ƶ̾ΰǤ:
.nf

    yy_create_buffer
    yy_delete_buffer
    yy_flex_debug
    yy_init_buffer
    yy_flush_buffer
    yy_load_buffer_state
    yy_switch_to_buffer
    yyin
    yyleng
    yylex
    yylineno
    yyout
    yyrestart
    yytext
    yywrap

.fi
(C++ ʻѻˤ
.B yywrap

.B yyFlexLexer
ƶޤ)
ʤǤϡХѿӴؿ
ɤ̾ǤǤ⻲ȤǤޤ;
ŪˤϽ̾Τ߻ޤ
.IP
ΥץѤ뤳Ȥˤꡢʣ
.I flex
ץƱμ¹Էưפ˥󥯤뤳Ȥޤ
Υץ
.B yywrap()
̾ѤޤΤǡ
ȼ(Ŭڤ̾դ)롼򥹥ʤΤѰդ뤫
.B %option noyywrap
Ѥ
.B \-ll
ȥ󥯤
.I ɬפޤ
ɤǥեȤǤ󶡤ޤ
.TP
.B \-Sskeleton_file
.I flex
ʤۤΤ˻ȤǥեȤ
ȥեͥ褷ޤ
.I flex
Υƥʥ󥹤䳫ȯ򤹤ʳΥץɬפޤ
.PP
.I flex
ϡflex Υޥɥ饤ǤϤʤ
ʻ͵椫饪ץ椹뵡󶡤ޤ
ϥʤκǽʬ
.B %option
ǥ쥯ƥ֤ޤ뤳ȤǼ¸Ǥޤ
ñ
.B %option
ǥ쥯ƥ֤ˤʣΥץǤ
ޤʣΥǥ쥯ƥ֤ flex ϥեκǽʬ֤Ȥޤ
.PP
ۤȤɤΥץñ̾Ǥꡢ
ץȤ "no" Ȥ(Ϥߤޤ)դ
̣ȿžǤޤ
ͤ flex Υե饰䤽ȿžǤ
.nf

    7bit            -7 ץ
    8bit            -8 ץ
    align           -Ca ץ
    backup          -b ץ
    batch           -B ץ
    c++             -+ ץ

    caseful ޤ
    case-sensitive  -i ץε(ǥե)

    case-insensitive ޤ
    caseless        -i ץ

    debug           -d ץ
    default         -s ץε
    ecs             -Ce ץ
    fast            -F ץ
    full            -f ץ
    interactive     -I ץ
    lex-compat      -l ץ
    meta-ecs        -Cm ץ
    perf-report     -p ץ
    read            -Cr ץ
    stdout          -t ץ
    verbose         -v ץ
    warn            -w ץε
                    (-w ץˤ "%option nowarn" ѤƲ)

    array           "%array" 
    pointer         "%pointer" (ǥե)

.fi
.B %option
ˤϡ¾ǤѤǤʤǽ󶡤Τ⤢ޤ:
.TP
.B always-interactive
Ϥ "Ū" ˰ʤ褦 flex ˻ؼޤ
̾ϥե˥ʤ
.B isatty()
ƤӽФʤϸŪǤ 1 ٤ 1 ʸɤ٤
ɤȽꤷ褦Ȥޤ
ΥץѤȤͤʸƤӽФϹԤޤ
.TP
.B main
ʤФ
.B yylex()
ƤӽФΥǥեȤ
.B main()
ץ󶡤褦˻ؼޤ
Υץ
.B noyywrap
()Ū˻ؼޤ
.TP
.B never-interactive
Ϥ "Ū" ȤϤʤʤ褦 flex ˻ؼޤ
(ޤ
.B isatty()
ƤӽФޤ)

.B always-interactive
εդǤ
.TP
.B stack
Ͼ凉åλѤͭˤޤ(ҤγϾ򻲾)
.TP
.B stdinit
ꤵƤ (ʤ
.B %option stdinit)
.I yyin

.I yyout

ǥեȤ
.I nil
ǤϤʤ
.I ɸ

.I ɸ
ꤷޤ
¸
.I lex
ץˤϡ
ANSI C ߴǤϤʤΤΡư˰¸ƤΤޤ
ANSI C Ǥ
.I ɸ

.I ɸ
ѥǤɬפϤޤ
.TP
.B yylineno
Ϥɤ߼äߤιֹ򥰥Хѿ
.B yylineno
ݻ륹ʤ褦ˡ
.I flex
˻ؼޤ
Υץ
.B %option lex-compat
Ū˻ꤵޤ
.TP
.B yywrap
åȤƤʤ (ʤ
.B %option noyywrap)
ʤϥեν˺ݤ
.B yywrap()
ƤФñ˥󤹤٤ե뤬⤦̵ΤȤ褦ˤʤޤ(
桼
.I yyin
򿷤եؤ褦ˤ
.B yylex()
ƤӽФޤǤǤ)
.PP
.I flex
ϥ롼륢򥹥󤷡
.B REJECT

.B yymore()
εǽȤƤ뤫ɤĴ٤ޤ
.B reject

.B yymore
ΥץѤȡ
ץǻꤷ̤ˤȽͥ褷ޤ
ץλϡåȤƵǽѤƤ뤳Ȥ򼨤(㤨
.B %option reject)
⤷ϥ󥻥åȤƵǽѤƤʤȤ򼨤(㤨
.B %option noyymore)
ΤȤޤ
.PP
Υץʸͤꡢ'=' Ƕڤޤ:
.nf

    %option outfile="ABC"

.fi

.B -oABC
ƱǤꡢ
.nf

    %option prefix="XYZ"

.fi

.B -PXYZ
ƱǤ
Ǹˡ
.nf

    %option yyclass="foo"

.fi
 C++ Τͭ(
.B \-+
ץ)Ǥ
.I flex
Фơ
.B foo

.B yyFlexLexer
Υ֥饹Ǥ뤳ȤΤ餻ޤΤǡ
.I flex
ϥ
.B yyFlexLexer::yylex()
ǤϤʤ
.B foo::yylex()
ΥдؿȤޤ
ޤ(
.B yyFlexLexer::LexerError()
ư뤳Ȥˤ)ƤӽФȼ¹Ի顼
.B yyFlexLexer::yylex()
дؿޤ
ܺ٤ϸҤ C++ ʤ򸫤Ʋ
.PP
줿ʤפʥ롼 lint ԤΤ
¿ΥץѰդƤޤ
ʲ򥢥󥻥åȤ(㤨
.B %option nounput
)б롼륹ʤޤ:
.nf

    input, unput
    yy_push_state, yy_pop_state, yy_top_state
    yy_scan_buffer, yy_scan_bytes, yy_scan_string

.fi
(
.B yy_push_state()

.B %option stack
Ѥʤˤϸޤ)
.SH ǽϢ
.I flex
μʥǥ󥴡Ϲǽʥʤ뤳ȤǤ
¿Υ롼륻åȤɤȤǺŬޤ
˳⤷
.B \-C
ץѤˤơ֥밵̤˵®٤ؤαƶ¾ˡ
ǽ򰭲¿Υץ/󤬤ޤ
ʤΤ²ʤΤؤ¤٤ޤ:
.nf

    REJECT
    %option yylineno
    ͳĹαʸ̮(trailing context)

    Хååפɬפʥѥ
    %array
    %option interactive
    %option always-interactive

    '^' Ƭڥ졼
    yymore()

.fi
ǽ 3 Ĥ˹ǤꡢǸ 2 Ĥ˰²Ǥ
.B unput()
Ū礭ʻŻ򤹤롼ƤӽФȤƼƤΤФ
.B yyless()
˰²ʥޥǤ;
Ǥ饹󤷤;ʬʥƥȤ᤹ξˤ
.B yyless()
ȤäƲ
.PP
ǽפʾˤϡ褦¤ϤǤä
.B REJECT
򤱤Ʋ
ä˹ʥץǤ
.PP
Хååפȡ𻨤ˤʤꡢ
Ҥɤϫʣʥʤ뤳Ȥˤʤޤ
ºŪˤ
.B \-b
ե饰ꤷ
.I lex.backup
ե뤳ȤϤޤ㤨С
.nf

    %%
    foo        return TOK_KEYWORD;
    foobar     return TOK_KEYWORD;

.fi
ФƤϡեϼΤ褦ˤʤޤ:
.nf

    State #6 is non-accepting -
     associated rule line numbers:
           2       3
     out-transitions: [ o ]
     jam-transitions: EOF [ \\001-n  p-\\177 ]

    State #8 is non-accepting -
     associated rule line numbers:
           3
     out-transitions: [ a ]
     jam-transitions: EOF [ \\001-`  b-\\177 ]

    State #9 is non-accepting -
     associated rule line numbers:
           3
     out-transitions: [ r ]
     jam-transitions: EOF [ \\001-q  s-\\177 ]

    Compressed tables always back up.

.fi
ǽοԤϡ
\&'o' ܤǤ뤬¾ʸˤܤǤʤ֤ꡢ
ξ֤Ǥϸߥ󤵤줿ƥȤ¾Υ롼ˤϥޥåʤȤ
ɽޤ
ξ֤ȯΤϡ
ϥեι 2, 3 Υ롼˥ޥå褦ȤǤ
ʤͤʾ֤ˤ 'o' ʳʸɤˤϡ
ޥå롼õΥХååפɬפȤʤޤ
ͤС "fo" 򸫤ˤ֤˰㤤ʤȤʬǤ礦
ͤʻ'o' ʳΤΤȡ
ʤϡñ 'f' ˥ޥå(ǥեȥ롼)Ȥޤ
(Хååפ)ޤ
.PP
 #8 ˴ط륳Ȥϡ
"foob" 󤵤줿꤬뤳ȤɽƤޤ
ºݡ'a' ʳʸ˽в񤦤ȡʤ "foo" Ȥޤޤ
Ʊͤ˾ #9 ˴ط륳Ȥϡ
"fooba" 󤵤 'r' ³ʤ˴طޤ
.PP
ǸΥȤΤΤϡ
.B \-Cf

.B \-CF
ȤäƤΤǤʤ
ХååפϤ뤳Ȥ̵̣Ǥ뤳ȤǤ
ʤʤ顢̤줿ʤФƤΤ褦ʤȤ򤷤Ƥ⡢
ǽפ̵Ǥ
.PP
Хååפˤ "顼" 롼ɲäޤ:
.nf

    %%
    foo         return TOK_KEYWORD;
    foobar      return TOK_KEYWORD;

    fooba       |
    foob        |
    fo          {
                /* false alarm, not really a keyword */
                return TOK_ID;
                }

.fi
.PP
ɤΥꥹȤХååפˤϡ"Ƥޤ"
롼Ѥ뤳Ȥޤ:
.nf

    %%
    foo         return TOK_KEYWORD;
    foobar      return TOK_KEYWORD;

    [a-z]+      return TOK_ID;

.fi
̾ŬڤʻˤϤϰɤǤ
.PP
Хååץåϥɤ뤳Ȥ¿Ǥ
ʣʥ롼ȤǤϡɴΥåΤ̤ΤȤǤ
ϤСХååפ뤿ˤ
ξΥ롼ˤط뤳ȤʬǤ礦
(ְ㤨뤳Ȥ¿ä롼뤬ͭʥȡ˥ޥåޤ

.I flex
εǽǤϡ
ưŪ˥Хååפ롼ɲä褦ˤʤ뤫Τޤ)
.PP
Хååפ뤳ȤˤפΤϡ
.I Ƥ
ХååפȤȤФƤȤϽפǤ
äĤĤƤⲿ뤳Ȥޤ
.PP
.I Ĺ
ʸ̮ (ʬȱʬΤ줫⤷ξĹ)
.B REJECT
ȤۤƱ(ʤ)ǽȤʤޤ
ΤἡΤ褦ʥ롼:
.nf

    %%
    mouse|rat/(cat|dog)   run();

.fi
ϼΤ褦˽񤯤:
.nf

    %%
    mouse/cat|dog         run();
    rat/cat|dog           run();

.fi
Τ褦˽񤤤ɤǤ:
.nf

    %%
    mouse|rat/cat         run();
    mouse|rat/dog         run();

.fi
̤ '|' ϽˤϤʤ
.I ޤ
äƾ򰭤ޤ
(Ҥη/Х򻲾)
.LP
ʤǽ夵뤿;(¸ϺǤư)ϡ
ޥåȡĹХʤ®ˤʤ뤳Ȥˤޤ
ĹȡǤϤۤȤɤϽ(û)롼פǽ졢
Τ˥ʴĶꤹɲäλŻ(㤨
.B yytext)
ۤȤɤʤǤ
C ȤΥʤפФޤ礦:
.nf

    %x comment
    %%
            int line_num = 1;

    "/*"         BEGIN(comment);

    <comment>[^*\\n]*
    <comment>"*"+[^*/\\n]*
    <comment>\\n             ++line_num;
    <comment>"*"+"/"        BEGIN(INITIAL);

.fi
Τ褦˽񤯤ȹ®ˤʤޤ:
.nf

    %x comment
    %%
            int line_num = 1;

    "/*"         BEGIN(comment);

    <comment>[^*\\n]*
    <comment>[^*\\n]*\\n      ++line_num;
    <comment>"*"+[^*/\\n]*
    <comment>"*"+[^*/\\n]*\\n ++line_num;
    <comment>"*"+"/"        BEGIN(INITIAL);

.fi
٤ϡ̤ΥνԤΤǤϤʤ
ǧϥ롼֤ "ʬ" 졢
ǽʸ¤ĹƥȤ˥ޥå褦ˤʤäƤޤ
롼
.I ɲ
ϥʤ٤
.I ޤ!
ʤ®٤ϡ롼Ȥ⡢
ڥ졼 '*'  '|' ȤäΤ˴Ť롼ʣ
(λϤǰޤ)ȤΩǤ
.\" ⼫̵Ǥ
.\" Apr 29 1997, horikawa@jp.freebsd.org
.PP
Ǹι®Ǥ:
1 Ԥ 1 ĤĤǤ̤ʸդʤ褦ʡ
̻Ҥȥɤƥե뤫饹󤹤뤳Ȥͤޤ
ǽϼΤ褦ˤʤǤ礦:
.nf

    %%
    asm      |
    auto     |
    break    |
    ... etc ...
    volatile |
    while    /* it's a keyword */

    .|\\n     /* it's not a keyword */

.fi
򤱤뤿Ƥޤ롼Ƴޤ:
.nf

    %%
    asm      |
    auto     |
    break    |
    ... etc ...
    volatile |
    while    /* it's a keyword */

    [a-z]+   |
    .|\\n     /* it's not a keyword */

.fi
1 ԤΤ 1 뤳ȤݾڤƤ硢
Ԥǧ̤Υȡʻ뤳Ȥǡ
ޥåȾʬ˸餹Ȥޤ:
.nf

    %%
    asm\\n    |
    auto\\n   |
    break\\n  |
    ... etc ...
    volatile\\n |
    while\\n  /* it's a keyword */

    [a-z]+\\n |
    .|\\n     /* it's not a keyword */

.fi
ǡ٥Хååפ򥹥ʤȤ߹Ȥ
դʤФʤޤ
º
.I 桹
ϥȥ꡼ϥ쥿ȲԤǤ뤳ȤΤäƤޤ
.I flex
Ϥ줬ʬʤᡢ
ȡ "auto" ʤɤ򥹥󤷤ʸԤǤ쥿Ǥʤˤ
ХååפɬפǤȹͤޤ
 "auto" 롼Ŭ礷ǽǤ
 "auto" 롼̵"auto\\n" 롼ޤ
Хååפβǽ뤿ˤϡ
Ǹβ԰ʳΥ롼Ų뤫
Τ褦Ϥ˽Ф蘆ʤΤʬפʬäƤ뤿ᡢ
ԤƳʤ⤦ĤƤޤ롼Ƴ뤳Ȥޤ:
.nf

    %%
    asm\\n    |
    auto\\n   |
    break\\n  |
    ... etc ...
    volatile\\n |
    while\\n  /* it's a keyword */

    [a-z]+\\n |
    [a-z]+   |
    .|\\n     /* it's not a keyword */

.fi
.B \-Cf
դƥѥ뤹ȡº
.I flex
ۤܺ®ˤʤޤ
.PP
Ǹջ:
.I flex
 NUL ˥ޥåˤ٤ȡʣ NUL ޤˤä٤Ǥ
ƥȤФ NUL ޤΤͽۤˤϡƥȤ
.I û
ʬȥޥå褦˥롼񤯤٤Ǥ
.PP
⤦Ĥǽ˴ؤǽջ:
ϤΥޥåˡǴ˼褦ˡ
礭ʥȡǼ뤿
.B yytext
ΥưŪѹȽ٤ʤޤ
ʤʤ顢()ȡƬ饹󤷤ʤͤФʤʤǤ
ǽפʾ硢
ƥȤ "礭" ʬ˥ޥå٤Ǥ "" ʬ˥ޥå
٤ǤϤޤ
ξԤκܤ 8K ʸ/ȡǤ
.SH C++ ʤ
.I flex
 2 ̤ C++ ˡ󶡤ޤ
ǽˡ
.I flex
ʤñ C ѥǤϤʤ C++ ѥ
ѥ뤹ȤΤǤ
ξ祳ѥ륨顼ˤϽвʤϤǤ
(դˤϺԤǸҤŻҥ᡼륢ɥ쥹𤷤Ʋ)
ξ롼ˤ C ɤǤϤʤ C++ ɤ񤯤Ȥޤ
ʤΥǥեȤϸ
.I yyin
ΤޤޤǤꡢ
ǥեȤΥ
.I yyout
ΤޤޤǤ뤳ȤդƲ
ɤ
.I FILE *
ѿΤޤޤǤꡢC++
.I streams
ǤϤʤǤ
.PP
.I flex
 C++ ʥ饹뤳Ȥޤ
.B \-+
ץꤹ(⤷Ū
.B %option c++
Ȥ)ȤΤ褦˼¹Ԥ졢
flex μ¹Է̾ '+' ǽäƤˤϼưŪ˻ꤵޤ
Υץꤹ flex 륹ʤΥǥեȤϥե
.B lex.yy.cc
Ȥʤ
.B lex.yy.c
ǤϤޤ
줿ʤ
2 Ĥ C++ 饹ȤΥ󥿥եإåե
.I FlexLexer.h
򥤥󥯥롼ɤޤ
.PP
ǽΥ饹
.B FlexLexer
ϰŪʥʥ饹ݴץ饹󶡤ޤ
ʲΥдؿ󶡤ޤ:
.TP
.B const char* YYText()
Ǹ˥ޥåƥȤ֤ޤ
.B yytext
Ǥ
.TP
.B int YYLeng()
Ǹ˥ޥåȡĹ֤ޤ
.B yyleng
Ǥ
.TP
.B int lineno() const
ߤϤιֹ(
.B %option yylineno
)⤷
.B %option yylineno
ѤƤʤˤ
.B 1
֤ޤ
.TP
.B void set_debug( int flag )
ʤΥǥХåե饰򥻥åȤޤ
.B yy_flex_debug
ΤƱǤ(ץ)
ʹۻ
.B %option debug
ѤƥǥХåȤ߹ɬפ뤳ȤդƲ
.TP
.B int debug() const
ߤΥǥХåե饰֤ޤ
.PP
ޤΤΤʥдؿ󶡤ޤ
.B yy_switch_to_buffer(),
.B yy_create_buffer()
(ǽΰ
.B istream*
֥ȥݥ󥿤Ǥ
.B FILE*
ǤϤޤ),
.B yy_flush_buffer(),
.B yy_delete_buffer(),
.B yyrestart()
(ޤǽΰ
.B istream*
֥ȥݥ󥿤Ǥ)
.PP
2 ܤΥ饹
.I FlexLexer.h

.B yyFlexLexer
Ǥꡢ
.B FlexLexer
ƳФΤǤ
ʲɲäΥдؿޤ:
.TP
.B
yyFlexLexer( istream* arg_yyin = 0, ostream* arg_yyout = 0 )
Ϳ줿ϥȥ꡼Ȥ
.B yyFlexLexer
֥Ȥۤޤ
ꤷʤˤϤ줾쥹ȥ꡼Υǥե
.B cin

.B cout
ˤʤޤ
.TP
.B virtual int yylex()

.B yylex()
̾ flex ʤФƹԤäΤƱͤôޤ:
롼Υ֤ͤޤǡ
ϥȥ꡼򥹥󤷡ȡ񤷤ޤ
.B yyFlexLexer
饵֥饹
.B S
ƳФ
.B yylex()

.B S
Υдؿѿ򥢥硢
.B %option yyclass="S"
ꤷ
.B yyFlexLexer
ǤϤʤ֥饹Ѥ뤳Ȥ
.I flex
Τ餻ɬפޤ
ξ
.B yyFlexLexer::yylex()
ΤǤϤʤ
.I flex

.B S::yylex()
(ӸƤӽФ줿ʤ
.B yyFlexLexer::LexerError()
ƤӽФߡ
.B yyFlexLexer::yylex()
)ޤ
.TP
.B
virtual void switch_streams(istream* new_in = 0,
.B
ostream* new_out = 0)
.B yyin

.B new_in
(˥ξ)
˺Ƴ
.B yyout

.B new_out
(Ʊ)˺Ƴޤ
.B yyin
Ƴ줿ˤϰϥХåեϾõޤ
.TP
.B
int yylex( istream* new_in, ostream* new_out = 0 )
ޤϥȥ꡼
.B switch_streams( new_in, new_out )
Ѥڤؤ
.B yylex()
֤ͤޤ
.PP
ˡ
.B yyFlexLexer
ϼΥץƥȤ줿۴ؿޤ
ʤˤ碌ƤƳХ饹ˤƺޤ:
.TP
.B
virtual int LexerInput( char* buf, int max_size )

.B max_size
ʸ
.B buf
ɤ߹ߡɤ᤿ʸ֤ޤ
Ϥν򼨤ˤ 0 ʸ֤ޤ"Ū" (
.B \-B

.B \-I
ե饰򻲾)ϥޥ
.B YY_INTERACTIVE
뤳ȤդƲ
.B LexerInput()

Ūϸ򥹥󤹤ǽ뤫ɤ˰¸
ۤʤ륢ɬפȤʤ硢
̾¸ߤ뤫ɤΥƥȤ
.B #ifdef
ˤƲǽǤ
.TP
.B
virtual void LexerOutput( const char* buf, int size )
.B size
ʸХåե
.B buf
񤭽Фޤ
ʤΥ롼뤬 NUL ޤƥȤ˥ޥåǽʾ硢
NUL üƤ뤳ΥХåե "" NUL ޤǤƤ⹽ޤ
.TP
.B
virtual void LexerError( const char* msg )
̿Ūʥ顼å𤷤ޤ
ǥեȤΤδؿϥå򥹥ȥ꡼
.B cerr
˽񤭡λޤ
.PP
.B yyFlexLexer
֥Ȥ
.I Ƥ
ξ֤ޤळȤդƲ
椨ͤʥ֥ȤꥨȥȤʥʤȤƻѤǤޤ
Ʊ
.B yyFlexLexer
饹ʣΥ󥹥󥹤βǽǤꡢ
ʣ C++ ʥ饹Ȥ߹碌嵭
.B \-P
ץѤ뤳ȤƱΥץǻѲǽǤ
.PP
Ǹ
.B %array
ǽ C++ ʥ饹ǤϻѤǤʤȤդƲ;
.B %pointer
ѤʤФʤޤ(ǥե)
.PP
ñ C++ ʤʲ˼ޤ:
.nf

        // An example of using the flex C++ scanner class.

    %{
    int mylineno = 0;
    %}

    string  \\"[^\\n"]+\\"

    ws      [ \\t]+

    alpha   [A-Za-z]
    dig     [0-9]
    name    ({alpha}|{dig}|\\$)({alpha}|{dig}|[_.\\-/$])*
    num1    [-+]?{dig}+\\.?([eE][-+]?{dig}+)?
    num2    [-+]?{dig}*\\.{dig}+([eE][-+]?{dig}+)?
    number  {num1}|{num2}

    %%

    {ws}    /* skip blanks and tabs */

    "/*"    {
            int c;

            while((c = yyinput()) != 0)
                {
                if(c == '\\n')
                    ++mylineno;

                else if(c == '*')
                    {
                    if((c = yyinput()) == '/')
                        break;
                    else
                        unput(c);
                    }
                }
            }

    {number}  cout << "number " << YYText() << '\\n';

    \\n        mylineno++;

    {name}    cout << "name " << YYText() << '\\n';

    {string}  cout << "string " << YYText() << '\\n';

    %%

    int main( int /* argc */, char** /* argv */ )
        {
        FlexLexer* lexer = new yyFlexLexer;
        while(lexer->yylex() != 0)
            ;
        return 0;
        }
.fi
ʣ(ۤʤä)ϥ饹硢
.B \-P
ե饰 (⤷
.B prefix=
ץ) ѤƳ
.B yyFlexLexer

.B xxFlexLexer
̤̾ˤޤ
˻ϥ饹ΥȤ
.B <FlexLexer.h>
򥤥󥯥롼ɤޤ
ʲΤ褦
.B yyFlexLexer
͡षޤ:
.nf

    #undef yyFlexLexer
    #define yyFlexLexer xxFlexLexer
    #include <FlexLexer.h>

    #undef yyFlexLexer
    #define yyFlexLexer zzFlexLexer
    #include <FlexLexer.h>

.fi
Ϥ륹ʤФ
.B %option prefix="xx"
Ѥ⤦Ф
.B %option prefix="zz"
ѤǤ
.PP
: ߤΥ󥯥饹η
.I ¸Ū
Ǥꡢ᥸㡼꡼Ѥ礭ѹǽޤ
.SH LEX  POSIX Ȥߴ
.I flex
 AT&T Unix 
.I lex
ġΥ饤ȤǤ(2 ĤμϤʤ륳ɤⶦͭޤ)
ФγĥߴäƤꡢ
ɤμǤǽʥʤ񤭤
ռʤФʤޤ
flex  POSIX
.I lex
ͤ˴פޤ㳰
.B %pointer
(ǥե)Ѥ
.B unput()
ƤӽФˤ
.B yytext
Ƥ˲뤳ȤǤꡢ POSIX ͤȿޤ
.PP
Ǥϡ
flex  AT&T lex  POSIX ͤȤδ֤ƤδΤߴ򰷤ޤ
.PP
.I flex

.B \-l
ץϥꥸʥ AT&T
.I lex
Ȥκθߴͭˤޤ
줿ʤǽ礭㲼ޤ
.B \-l
ץѤƤȯߴϸǽҤ٤ޤ
.PP
.I flex
ϰʲ㳰
.I lex
ȴߴǤ:
.IP -
ɥȤ˵ܤƤʤ
.I lex
ѿ
.B yylineno

.B \-l
⤷
.B %option yylineno
ѤʤȥݡȤޤ
.IP
.B yylineno
ϥ(ñΥХѿ)ǤϤʤХåե˴٤Ǥ
.IP
.B yylineno
 POSIX ͤǤϤޤ
.IP -
.B input()
롼ϺǤޤ󤬡
롼˥ޥåΤ˸³ʸɤि˸ƤФ줨ޤ
.B input()
եνãȡ̾
.B yywrap()
Ͻλޤ``ºݤ'' եν
.I EOF
Ȥ֤ޤ
.IP
ºݤˤϤ
.B YY_INPUT
ޥ뤳Ȥˤ椵ޤ
.IP
.B input()
ǤʤȤ
.I flex
¤ϡǽ
.I yyin
ꤹʳΥˡñ˵ꤷƤʤȤ
POSIX ͤȹפޤ
.IP -
.B unput()
롼ϺǤޤ󡣤¤ POSIX ˹פƤޤ
.IP -
.I flex
ʤ
.I lex
ʤȤϰۤʤꥨȥȤǤϤޤ
ºݡŪʥʤˤơ
ߥϥɥˤƥ󥰥פѤƥʤæФ
θ她ʤٸƤӽФ硢ʲΥåǤ礦:
.nf

    fatal flex scanner internal error--end of buffer missed

.fi
ʤ˺뤿ˤϡޤʲΤ褦ˤƲ
.nf

    yyrestart( yyin );

.fi
θƤӽФˤϥХåեϼΤƤ뤳ȤդƲ;
̾盧ŪʤǤǤϤޤ
.IP
ޤC++ ʥ饹ϥꥨȥ
.I Ǥ
ΤǡC++ ѤǤΤʤ顢C++ Ѥ٤Ǥ
Ҥ "C++ ʤ" 򻲾ȤƲ
.IP -
.B output()
ϥݡȤƤޤ
.B ECHO
ޥνϤϥեݥ
.I yyout
(ǥեȤǤ
.I ɸ
)ФƹԤޤ
.IP
.B output()
 POSIX ͤˤϤޤ
.IP -
.I lex
¾ŪϾ (%x) 򥵥ݡȤޤ󤬡 POSIX ͤˤޤ
.IP -
Ÿ
.I flex
Ǥϳ̤ǳޤ
lex Ǥϰʲ:
.nf

    NAME    [A-Z][A-Z0-9]*
    %%
    foo{NAME}?      printf( "Found it\\n" );
    %%

.fi
ʸ "foo" ˤϥޥåޤ
ʤʤŸ줿ޥϥ롼 "foo[A-Z][A-Z0-9]*?" ˤʤꡢ
ͥ٤ˤ `?'  "[A-Z0-9]*" ȷդޤ
.I flex
Ǥϥ롼뤬Ÿ "foo([A-Z][A-Z0-9]*)?" Ȥʤꡢ
ʸ "foo" ޥåޤ
.IP
.B ^
ǻϤޤ뤫
.B $
ǽϡŸ˳̤ǳ餺
Υڥ졼ˤ̤ʰ̣򼺤ʤ褦ˤ뤳Ȥ
դƲ

.B <s>, /,
.B <<EOF>>
ڥ졼
.I flex
ǤϻѤǤޤ
.IP
.B \-l
Ѥȡ
.I lex
ο񤤤Ʊ̤ǳޤ
.IP
POSIX ͤǤϡ̤ǳޤ
.IP -
.I lex
μˤäƤϡ
롼Υѥα¦˶򤬤硢
롼Υ̤ιԤϤ뤳Ȥޤ:
.nf

    %%
    foo|bar<space here>
      { foobar_action(); }

.fi
.I flex
Ϥεǽ򥵥ݡȤޤ
.IP -
.I lex

.B %r
(Ratfor ʤ)ץϥݡȤƤޤ
 POSIX ͤˤϴޤޤޤ
.IP -
ʤ
.B %array
ѤƹۤΤǤϤʤ¤ꡢ
.B unput()
ƤӽФˤϡΥȡ˥ޥåޤ
.I yytext
̤Ǥ

.I lex
ˤ POSIX ͤˤƤϤޤޤ
.B \-l
ץꤹȤߴޤ
.IP -
.B {}
(ϰ)ڥ졼ͥ٤ۤʤޤ
.I lex
 "abc{1,3}"  "1 ٤ 2 ٤ 3 ٤ 'abc' ˥ޥå" Ȳᤷޤ
.I flex
 "'ab'  1 ٤ 2 ٤ 3 ٤ 'c' ³Τ˥ޥå" Ȳᤷޤ
Ԥ POSIX ͤ˹פޤ
.IP -
.B ^
ڥ졼ͥ٤ۤʤޤ
.I lex
 "^foo|bar"  "Ƭ 'foo' Ǥհ֤ 'bar' ˥ޥå" Ȳᤷޤ
.I flex
 "Ƭ 'foo'  'bar' ˥ޥå" Ȳᤷޤ
Ԥ POSIX ͤ˹פޤ
.IP -
.I lex
ǥݡȤƤ
.B %a
̤ʥơ֥륵
.I flex
ʤǤפǤ;
.I flex
Ϥ̵뤷ޤ
.IP -
.I flex

.I lex
ΤɤǤ⥹ʤѲǽ˽񤱤褦ˡ
.bd
FLEX_SCANNER
Ȥ̾ޤ
ʤ
.I flex
ΥСɽ
.B YY_FLEX_MAJOR_VERSION

.B YY_FLEX_MINOR_VERSION
򡢥ʤϴޤߤޤ
(㤨 2.5 ꡼ǤϤϤ줾 2  5 ˤʤޤ)
.PP
ʲ
.I flex
εǽ
.I lex
 POSIX ͤˤϴޤޤޤ:
.nf

    C++ 
    %option
    Ͼ凉
    Ͼ凉å
    Ū/Ū
    yy_scan_string() 
    yyterminate()
    yy_set_interactive()
    yy_set_bol()
    YY_AT_BOL()
    <<EOF>>
    <*>
    YY_DECL
    YY_START
    YY_USER_ACTION
    YY_USER_INIT
    #line ǥ쥯ƥ
    μ %{}
    ñԤˤʣΥ

.fi
ˤۤƤ flex ե饰Ǥ
ꥹȤκǸεǽΰ̣ϡ
.I flex
ǤʣΥ򥻥ߥǶڤäƱԤ˵ҲǽǤ
.I lex
Ǥϼ
.nf

    foo    handle_foo(); ++num_foos_seen;

.fi
 (ä٤Ȥ) Τ褦ڤͤȤȤǤ
.nf

    foo    handle_foo();

.fi
.I flex
ϥڤͤޤ
֥졼ǳʤñ˹ǽλޤ
.SH 
.I warning, rule cannot be matched
ƱƥȤ˥ޥå롼뤬ˤΤǡ
Ϳ줿롼뤬ޥåޤ
㤨аʲ "foo"  "Ƥޤ" 롼θˤޤΤ
褷ƥޥåޤ:
.nf

    [a-z]+    got_identifier();
    foo       got_foo();

.fi

.B REJECT
ѤȤηٹޤ
.PP
.I warning,
.B \-s
.I
option given but default rule can be matched
(餯γϾΤȤǤ)
ǥեȥ롼 (Ǥդΰʸ˥ޥå) Ϥ
ФƤϥޥåʤȤޤ
.B \-s
ꤷƤΤǡ餯ʤޤ
.PP
.I reject_used_but_not_detected undefined
뤤
.I yymore_used_but_not_detected undefined -
Υ顼 ѥ˵ޤʤ
.B REJECT
⤷
.B yymore()
ȤäƤޤ
.I flex
ΤȤ˵ŤʤäȤȤǤ
Ĥޤꡢ
.I flex
Ϻǽ 2 ĤʬõƤ
Υνи򸫤ĤʤäΤǤ
ºݤˤϲ餫ˡ
(㤨 #include ե𤷤)Ǥ餬ҤƤȤȤǤ
.B %option reject

.B %option yymore
Ѥơflex ˤεǽºݤ˻ѤƤ뤳Ȥ򶵤Ʋ
.PP
.I flex scanner jammed -
.B \-s
ǥѥ뤵줿ʤɤΥ롼ˤޥåʤ
ʸޤ
Ū˵ƤΥ顼뤳Ȥ⤢ޤ
.PP
.I token too large, exceeds YYLMAX -
ʤ
.B %array
ȤäƤˡ롼뤬
.B YYLMAX
(ǥեȤ 8K Х) 礭ʸȥޥåޤ
.I flex
ϥե
.B YYLMAX
 #define 뤳Ȥͤ礭Ǥޤ
.PP
.I scanner requires \-8 flag to
.I use the character 'x' -
ʤεҤ 8 ӥåȤʸ
.I 'x'
̤ʬꡢ
.B \-Cf
⤷
.B \-CF
Υơ֥밵̥ץΤ˥ǥեȤ 7 ӥåȤˤʤäƤ
ˤ⤫餺
\-8 ץĤƤʤȤȤǤ
ܺ٤
.B \-7
ե饰Υץε򻲾ȤƲ
.PP
.I flex scanner push-back overflow -
.B unput()
ǥƥȤᤷᡢʤΥХåե
ᤷƥȤȸȡ
.B yytext
ݤƤޤ
ξ硢ŪˤϥʤưŪ˥Хåե礭Ѥ٤Ǥ
ߤΤȤʤäƤϤޤ
.PP
.I
input buffer overflow, can't enlarge buffer because scanner uses REJECT -
ʤ礭ʥȡΥޥåĴ٤ƤơϥХåե
ĥɬפޤʤ顢Хåեγĥ
.B
REJECT
ȤʤǤƯޤ
.PP
.I
fatal flex scanner internal error--end of buffer missed -
ʤѤƤե졼फ(ۤ)󥰥פ塢
٥ʤä˵ޤ
٥ʤ:
.nf

    yyrestart( yyin );

.fi
ȤҤΤ褦 C++ ʥ饹Ѥ褦ˤƲ
.PP
.I too many start conditions in <> construct! -
¸ߤ¿γϾ <> ˵ܤޤ
(ʤȤĤٵܤޤ)
.SH Ϣե
.TP
.B \-ll
ʤ󥯤ʤФʤʤ饤֥ꡣ
.TP
.I lex.yy.c
줿(ƥˤäƤ
.I lexyy.c
Ȥ̾ˤʤޤ)
.TP
.I lex.yy.cc
.B -+
Ȥä˺줿 C++ ʥ饹
.TP
.I <FlexLexer.h>
C++ ʥ١饹
.B FlexLexer
ȤƳХ饹
.B yyFlexLexer
إåե롣
.TP
.I flex.skl
ȥ󥹥ʡ
Υե flex μ¹ԻǤϤʤflex ۤΤѤޤ
.TP
.I lex.backup
.B \-b
ե饰ѤΥХåå׾(ƥˤäƤ
.I lex.bck
Ȥ̾ˤʤޤ)
.SH  / Х
ʸ̮(trailing context)ѥˤϡޥå
ٹå ("dangerous trailing context") ФΤޤ
Υѥϡ
롼κǽʬ 2ܤƬʬȥޥå褦ʤΤǤ
㤨 "zx*/xy*" ξ硢'x*' ϱʸ̮Ƭ 'x' ȥޥåޤ
(POSIX ɥեȤǤϤΤ褦ʥѥ˥ޥåƥȤ
̤ǤȽҤ٤Ƥ뤳ȤդƲ)
.PP
ʸ̮ˤϡºݤˤϸĹǤΤˤȤϲᤵʤΤꡢ
˽Ҥ٤ǽ㲼ޤ
äˡ '|'  {n} (㤨 "foo{3}") Ͼ˲ĹǤȲᤵޤ
.PP
ʸ̮̤ʥ '|' Ȥ߹碌
.I 
ʸ̮ꥳȤΤ
.I Ѥ
ʸ̮Ȥʤޤ㤨СΤ褦ʤΤǤ:
.nf

    %%
    abc      |
    xyz/def

.fi
.PP
.B %array
⤷
.B \-l
ץꤷʤ硢
.B unput()
Ȥ yytext  yyleng ˲ޤ
.PP
NUL Υѥޥå󥰤¾ʸӤ꤫ʤ٤ʤäƤޤ
.PP
ϥХåեưŪ礭κĴϻ֤ޤϸȡ
(̤˵)ޤǤΥޥåƥȤκƥȼǤ
.PP
ϤΥХåե󥰤ɤߤΤᡢ <stdio.h> 롼
礷ƻȤȤޤ㤨С
.B getchar()

.I flex
Υ롼ϤޤԤޤ
.B input()
ȤäƲ
.PP
.B \-v
ץɽơ֥륨ȥˤϡ
ɤΥ롼뤬ޥåΤꤹΤɬפʥơ֥륨ȥ
ޤޤƤޤ󡣥ȥοϥʤ
.B REJECT
ȤäƤʤȤˤ DFA ֿ
ȤäƤȤˤ DFA ֿꤤ餫礭ʤޤ
.PP
.B REJECT
ץ
.B \-f
⤷
.B \-F
ȤȤ˻Ȥޤ
.PP
.I flex
르ꥺˤĤƤΥɥȤɬפǤ
.SH Ϣ
lex(1), yacc(1), sed(1), awk(1)
.PP
John Levine, Tony Mason, and Doug Brown,
.I Lex & Yacc,
O'Reilly and Associates.
 2 Ǥꤹ뤳ȡ
.PP
M. E. Lesk and E. Schmidt,
.I LEX \- Lexical Analyzer Generator
.PP
Alfred Aho, Ravi Sethi and Jeffrey Ullman,
.I Compilers: Principles, Techniques and Tools,
Addison-Wesley (1986).
.I flex
ǻѤƤѥޥå󥰵ˡ⤷Ƥ(ȥޥȥ)
.SH 
Vern Paxson ¿Υǥȥ󥹥ԥ졼
Van Jacobson ޤ
ꥸʥС Jef Poskanzer ޤ
®ơ֥ɽ Van Jacobson ΥǥʬǤ
μ Kevin Gong  Vern Paxson Ԥޤ
.PP
¿
.I flex
١ƥեɥХåȥӥ塼ä Francois Pinard,
Casey Leedom,
Robert Abramovitz,
Stan Adermann, Terry Allen, David Barker-Plummer, John Basrai,
Neal Becker, Nelson H.F. Beebe, benson@odi.com,
Karl Berry, Peter A. Bigot, Simon Blanchard,
Keith Bostic, Frederic Brehm, Ian Brockbank, Kin Cho, Nick Christopher,
Brian Clapper, J.T. Conklin,
Jason Coughlin, Bill Cox, Nick Cropper, Dave Curtis, Scott David
Daniels, Chris G. Demetriou, Theo Deraadt,
Mike Donahue, Chuck Doucette, Tom Epperly, Leo Eskin,
Chris Faylor, Chris Flatters, Jon Forrest, Jeffrey Friedl,
Joe Gayda, Kaveh R. Ghazi, Wolfgang Glunz,
Eric Goldman, Christopher M. Gould, Ulrich Grepel, Peer Griebel,
Jan Hajic, Charles Hemphill, NORO Hideo,
Jarkko Hietaniemi, Scott Hofmann,
Jeff Honig, Dana Hudes, Eric Hughes, John Interrante,
Ceriel Jacobs, Michal Jaegermann, Sakari Jalovaara, Jeffrey R. Jones,
Henry Juengst, Klaus Kaempf, Jonathan I. Kamens, Terrence O Kane,
Amir Katz, ken@ken.hilco.com, Kevin B. Kenny,
Steve Kirsch, Winfried Koenig, Marq Kole, Ronald Lamprecht,
Greg Lee, Rohan Lenard, Craig Leres, John Levine, Steve Liddle,
David Loffredo, Mike Long,
Mohamed el Lozy, Brian Madsen, Malte, Joe Marshall,
Bengt Martensson, Chris Metcalf,
Luke Mewburn, Jim Meyering, R. Alexander Milowski, Erik Naggum,
G.T. Nicol, Landon Noll, James Nordby, Marc Nozell,
Richard Ohnemus, Karsten Pahnke,
Sven Panne, Roland Pesch, Walter Pelissero, Gaumond
Pierre, Esmond Pitt, Jef Poskanzer, Joe Rahmeh, Jarmo Raiha,
Frederic Raimbault, Pat Rankin, Rick Richardson,
Kevin Rodgers, Kai Uwe Rommel, Jim Roskind, Alberto Santini,
Andreas Scherer, Darrell Schiebel, Raf Schietekat,
Doug Schmidt, Philippe Schnoebelen, Andreas Schwab,
Larry Schwimmer, Alex Siegel, Eckehard Stolz, Jan-Erik Strvmquist,
Mike Stump, Paul Stuart, Dave Tallman, Ian Lance Taylor,
Chris Thewalt, Richard M. Timoney, Jodi Tsai,
Paul Tuinenga, Gary Weik, Frank Whaley, Gerhard Wilhelms, Kent Williams, Ken
Yap, Ron Zellar, Nathan Zelle, David Zuhn,
ӻκΥ᡼륢ǽϤ
ζϤˤƱͤ˴դޤ
.PP
Keith Bostic, Jon Forrest, Noah Friedman,
John Gilmore, Craig Leres, John Levine, Bob Mulcahy, G.T.
Nicol, Francois Pinard, Rich Salz, Richard Stallman
ˤ¿Ǻߤʬ˴ؤƴդޤ
.PP
Esmond Pitt  Earle Horton ˤ 8 ӥåʸݡȤ˴ؤ;
Benson Margulies  Fred Burke ˤ C++ ݡȤ˴ؤ;
Kent Williams  Tom Epperly ˤ C++ 饹ݡȤ˴ؤ;
Ove Ewerlid ˤ NUL ΥݡȤ˴ؤ;
Eric Hughes ˤʣХåեΥݡȤ˴ؤơ줾촶դޤ
.PP
κʤ顢䤬 CA Berkeley  Lawrence Berkeley Laboratory
ˤ Real Time Systems Group ˤ˺ޤ
˶ϤƤ줿˴դޤ
.PP
Ȥ vern@ee.lbl.gov äƲ