readme.svn-base

类似QQ的功能

                        SiJaPP - Simple Java PreProcessor

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README
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ABOUT

SiJaPP is a simple Java preprocessor. It supports conditional compiling. A
SiJaPP statement looks like this:

  #sijapp <COMMAND>[.<SUBCOMMAND>] <PARAMETERS> #

The rest of the line is ignored. Each statement must not span across multiple
lines and only the first statement per line is evaluated.

Currently the following commands are available:

  *  cond.[if|elseif] <EXPR>
     cond.[else|end]
       With these commands it is possible to include/exclude code sections
       based on whether certain conditions hold or not.
       Code is excluded by commenting it out. Special SiJaPP comments (lines
       that start with //#) are removed before the line is processed. You can
       use this to exclude areas of conditional code from normal Java 
       compilation (e.g. in IDE).

  *  echo <STRING>
       Prints the specified string.

  *  env.def <IDENT> [<STRING>]
     env.undef <IDENT>
       Set/unset variables locally. <STRING> defaults to "defined".

  *  exit
       Rest of the file is ignored.

SiJaPP supports the following operators, listed in order of descending
precedence:

  *  Equal             "="  "is"      L/2  <IDENT>,<STRING>,"defined"/<BOOL>
  *  Not equal         "!=" "isnot"   L/2  <IDENT>,<STRING>,"defined"/<BOOL>
  *  Conditional NOT   "!"  "not"     R/1  <BOOL>                    /<BOOL>
  *  Conditional AND   "&"  "and"     L/2  <BOOL>                    /<BOOL>
  *  Conditional OR    "|"  "or"      L/2  <BOOL>                    /<BOOL>

Default operator precedence can be overriden through the use of parentheses,
to explicitly specify the order of operations.

Strings are enclosed by double quotes. Double quotes and backslashes have to be
escaped by using a backslash. Other escape sequences are not supported.

All identifiers have to start with a alphabetic character or an underscore,
optionally followed by one or more alphanumerical characters and underscores.

Identifiers and keywords are case-sensitive.

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TOKENS

  *  MAGIC_BEGIN     "#sijapp"
  *  MAGIC_END       "#"
  *  IDENT           [A-Za-z_][A-Za-z0-9_]* -- e.g. foobar, _DEBUG, WIN98
  *  STRING          Characters enclosed by double quotes -- e.g. "foobar"
  *  BOOL            "true" "false"
  *  SEP             "."
  *  CMD1_COND       "cond" "condition"
  *  CMD1_ECHO       "echo"
  *  CMD1_ENV        "env" "environment"
  *  CMD1_EXIT       "exit"
  *  CMD2_IF         "if"
  *  CMD2_ELSEIF     "elseif"
  *  CMD2_ELSE       "else"
  *  CMD2_END        "end"
  *  CMD2_DEF        "def" "define"
  *  CMD2_UNDEF      "undef" "undefine"
  *  EXPR_PRS_LEFT   "("
  *  EXPR_PRS_RIGHT  ")"
  *  EXPR_EQ         "=" "is"
  *  EXPR_NEQ        "!=" "isnot"
  *  EXPR_NOT        "!" "not"
  *  EXPR_AND        "&" "and"
  *  EXPR_OR         "|" "or"
  *  EXPR_DEF        "defined"

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DETERMINISTIC FINITE AUTOMATON

||                         [A-Za-z0-9_]
||                      /----------------\
||                     |                  |
||  #      [A-Za-z_]   |                  |
||----->Q------------->Q<----------------/
||      1              2
||
||                  [A-Za-z0-9_]
||               /----------------\
||              |                  |
||  [A-Za-z_]   |                  |
||------------->Q<----------------/
||              3
||  .
||----->Q
||      4
||
||       /-----\
||      |       |
||      |       |
||       \     /
||        \   /
||    "    \ V   "
||--------->O--------->Q
||          5          6
||         ^ \
||        /   \
||       /     \
|| [\"] |       | \
||      |       |
||       \--O<-/
||          7
||  [ \t]
||--------->Q
||          8
||  (
||----->Q
||      9
||  )
||----->Q
||     10
||  =
||----->Q
||     11
||  !      =
||----->Q----->Q
||     12     13
||  &
||----->Q
||     14
||  |
||----->Q
||     15

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GRAMMAR (BNF)

  *  <all> ::= MAGIC_BEGIN <cmd> MAGIC_END
  *  <cmd> ::= CMD1_COND SEP CMD2_IF <expr>
             | CMD1_COND SEP CMD2_ELSEIF <expr>
             | CMD1_COND SEP CMD2_ELSE
             | CMD1_COND SEP CMD2_END
             | CMD1_ECHO STRING
             | CMD1_ENV SEP CMD2_DEF IDENT
             | CMD1_ENV SEP CMD2_DEF IDENT STRING
             | CMD1_ENV SEP CMD2_UNDEF IDENT
             | CMD1_EXIT
  *  <expr> ::= EXPR_PRS_LEFT <expr> EXPR_PRS_RIGHT
              | <term> EXPR_EQ <term>
              | <term> EXPR_NEQ <term>
              | EXPR_NOT <expr>
              | <expr> EXPR_AND <expr>
              | <expr> EXPR_OR <expr>
  *  <term> ::= IDENT
              | STRING
              | EXPR_DEF

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LICENSING

For licensing and copyright information, please see the file COPYING in the
SiJaPP distribution.

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CREDITS

SiJaPP is written by Manuel Linsmayer <manuel at jimm.org>.