The Gedcom parser library
- -The intention of this page is to provide some explanation
- of the gedcom parser, to aid development on and with it. First, some
-practical issues of testing with the parser will be explained.
-
- -Basic testing
- You should be able to perform a basic test using the commands:
- + + +The Gedcom parser library internals
+
+
+
+This basic description ignores the problem of character encoding.
+
+
+ +
+GEDCOM defines three standard encodings:
+
+ + + + + +
+
+
+ -
- -
Basic testing
-
- You should be able to perform a basic test using the commands:- + + +
+
-
-
-
+For each recognized statement in the GEDCOM file, the parser calls some callbacks,
+which can be registered by the application to get the information out of
+the file.The Gedcom parser library internals
+ +The intention of this page is to provide some explanation
+ of the gedcom parser, to aid development on and with it. First,
+some practical issues of testing with the parser will be explained.
+
+
+
+Testing
+
+
+Basic testing
+
+ You should be able to perform a basic test using the commands:
+
-
- -
-
- However, since the output that
-
- For the first issue, the UTF-8 capable terminal, the safest bet is -to use
+ make check
+ + If everything goes OK, you'll see that some gedcom files are parsed, + and that each parse is successful. Note that some of the used gedcom files + are made by Heiner + Eichmann and are an excellent way to test gedcom parsers thoroughly.
+
+ + +
+
+ However, since the output that
+
+ For the first issue, the UTF-8 capable terminal, the safest bet is + to use
-
- For the second issue, you'll need the ISO 10646-1 fonts. These - come also with XFree86 4.0.x.
-
- The way to start
- -
-
- -
- -
-
- For the ANSEL test file (
- +
+ For the second issue, you'll need the ISO 10646-1 fonts. These + come also with XFree86 4.0.x.
+
+ The way to start
+ +
+
+ + +
+ +
+
+ For the ANSEL test file (
+
-
- -
- -
-
- This concludes the testing setup. Now for some explanations...
-
- -
-
-
-
-
-
- TO BE COMPLETED...
- -
-
+ + This is because for the ANSEL character set an extra module is needed + for the iconv library (more on this later). But again, this should + show a lot of special characters.
+
+ + +
+ +
+
+ This concludes the testing setup. Now for some explanations...
+
+ + +
+
+
+
+
+
+ The parser is based on
-
- +
+
Index
+-
+
- Testing +
- Basic testing +
- Preparing for further testing +
- Testing the parser with debugging +
- Testing the lexers separately
+
+ - Structure of the parser +
- Character encoding
+
+
-
+
-
+
+
+
Testing
+
+
+
+Basic testing
+
+
+
+ You should be able to perform a basic test using the commands:+
- If everything goes OK, you'll see that some gedcom files are parsed, - and that each parse is successful. Note that the used gedcom files - are made by Heiner - Eichmann and are an excellent way to test gedcom parsers thoroughly../configure
- make
- make check
-
-
- -
Preparing for further testing
- The basic testing described above doesn't show anything else than -"Parse succeeded", which is nice, but not very interesting. Some -more detailed tests are possible, via thetestgedcom program
-that is generated by make test. -
- However, since the output that
testgedcom generates is
- in UTF-8 format (more on this later), some preparation is necessary to
-have a full view on it. Basically, you need a terminal that understands
- and can display UTF-8 encoded characters, and you need to proper fonts installed
- to display them. I'll give some advice on this here, based on the
- Red Hat 7.1 distribution that I use, with glibc 2.2 and XFree86 4.0.x. Any
- other distribution that has the same or newer versions for these components
- should give the same results.-
- For the first issue, the UTF-8 capable terminal, the safest bet is -to use
xterm in its unicode mode (which is supported by the
- xterm coming with XFree86 4.0.x). UTF-8 capabilities
- have only recently been added to gnome-terminal, so probably
+ make+ make check
+ + If everything goes OK, you'll see that some gedcom files are parsed, + and that each parse is successful. Note that some of the used gedcom files + are made by Heiner + Eichmann and are an excellent way to test gedcom parsers thoroughly.
+
+ + +
Preparing for further testing
+Some +more detailed tests are possible, via thetestgedcom program
+that is generated by make. +
+ However, since the output that
testgedcom generates
+is in UTF-8 format (more on this later), some preparation is necessary
+to have a full view on it. Basically, you need a terminal that understands
+ and can display UTF-8 encoded characters, and you need to proper fonts
+installed to display them. I'll give some advice on this here,
+based on the Red Hat 7.1 distribution that I use, with glibc 2.2 and XFree86
+4.0.x. Any other distribution that has the same or newer versions
+for these components should give the same results.+
+ For the first issue, the UTF-8 capable terminal, the safest bet is + to use
xterm in its unicode mode (which is supported by
+the xterm coming with XFree86 4.0.x). UTF-8 capabilities
+ have only recently been added to gnome-terminal, so probably
that is not in your distribution yet (it certainly isn't in Red Hat 7.1).-
- For the second issue, you'll need the ISO 10646-1 fonts. These - come also with XFree86 4.0.x.
-
- The way to start
xterm in unicode mode is then e.g. (put
- everything on 1 line !):- -
- This first sets theLANG=en_GB.UTF-8 xterm -bg 'black' -fg 'DarkGrey' -cm - -fn '-Misc-Fixed-Medium-R-SemiCondensed--13-120-75-75-C-60-ISO10646-1'
-
LANG variable to a locale that
- uses UTF-8, and then starts xterm with a proper Unicode font.
- Some sample UTF-8 plain text files can be found
- here . Just cat them on the command line
-and see the result.-
- -
Testing the parser with debugging
- Given the UTF-8 capable terminal, you can now let thetestgedcom
- program print the values that it parses. An example of a command
- line is (in the gedcom directory):- -
- The./testgedcom -dg t/ulhc.ged
-
-dg option instructs the parser to show its own debug
- messages (see ./testgedcom -h for the full set of options).
- If everything is OK, you'll see the values from the gedcom file, containing
- a lot of special characters.-
- For the ANSEL test file (
t/ansel.ged), you have to set
-the environment variable GCONV_PATH to the ansel
- subdirectory of the gedcom directory:- +
+ For the second issue, you'll need the ISO 10646-1 fonts. These + come also with XFree86 4.0.x.
+
+ The way to start
xterm in unicode mode is then e.g.
+(put everything on 1 line !):+ +
+ This first sets theLANG=en_GB.UTF-8 xterm -bg 'black' -fg 'DarkGrey' -cm + -fn '-Misc-Fixed-Medium-R-SemiCondensed--13-120-75-75-C-60-ISO10646-1'
+
LANG variable to a locale that
+ uses UTF-8, and then starts xterm with a proper Unicode font.
+ Some sample UTF-8 plain text files can be found
+ here . Just cat them on the command line
+ and see the result.+
+ + +
Testing the parser with debugging
+ + Given the UTF-8 capable terminal, you can now let thetestgedcom
+ program print the values that it parses. An example of a command
+ line is (in the top + +
+ The./testgedcom -dg t/input/ulhc.ged
+
-dg option instructs the parser to show its own debug
+ messages (see ./testgedcom -h for the full set of options).
+ If everything is OK, you'll see the values from the gedcom file,
+containing a lot of special characters.+
+ For the ANSEL test file (
t/ansel.ged), you have to set
+ the environment variable GCONV_PATH to the ansel
+ subdirectory of the top directory:+
export GCONV_PATH=./ansel
- ./testgedcom -dg t/ansel.ged
- -
- -
Testing the lexers separately
- The lexers themselves can be tested separately. For the 1-byte - lexer (i.e. supporting the encodings with 1 byte per characters, such -as ASCII, ANSI and ANSEL), the sequence of commands would be:- -
make clean
- make test_1byte
- t/allged.ged test file. Similar
- tests can be done using make test_hilo and make test_lohi
- (for the unicode lexers).-
- This concludes the testing setup. Now for some explanations...
-
- -
Structure of the parser
- I see the structure of a program using the gedcom parser as follows:-
-
- -
-
- TO BE COMPLETED...
- -
-
$Id$+ ./testgedcom -dg t/input/ansel.ged
$Name$
+ + This is because for the ANSEL character set an extra module is needed + for the iconv library (more on this later). But again, this should + show a lot of special characters.
+
+ + +
Testing the lexers separately
+ + The lexers themselves can be tested separately. For the 1-byte + lexer (i.e. supporting the encodings with 1 byte per characters, such as + ASCII, ANSI and ANSEL), the command would be (in thegedcom subdirectory):+ +
make lexer_1byte
+ t/input/allged.ged
+ test file. Simply cat the file through the lexer on standard input
+and you should get all the tokens in the file. Similar tests can be
+done using make lexer_hilo and
+make lexer_lohi
+ (for the unicode lexers). In each of the cases you need to know
+yourself which of the test files are appropriate to pass through the lexer.+
+ This concludes the testing setup. Now for some explanations...
+
+ + +
Structure of the parser
+ I see the structure of a program using the gedcom parser as follows:+
+
+ +
+
+ The parser is based on
lex/yacc, which means that a module generated by lex
+ takes the inputfile and determines the tokens in that file (i.e. the smallest
+units, such as numbers, line terminators, GEDCOM tags, characters in GEDCOM
+values...). These tokens are passed to the parser module, which is
+generated by yacc, to parse the syntax of the file, i.e. whether the tokens
+appear in a sequence that is valid. -
+
+This basic description ignores the problem of character encoding.
+
+
Character encoding
Refer to this page for some introduction on character encoding...+ +
+GEDCOM defines three standard encodings:
+
-
+
- ASCII +
- ANSEL +
- UNICODE (assumed to be UCS-2, either big-endian or little-endian: the GEDCOM spec doesn't specify this) +
+ + + + + +
+
$Id$+
$Name$
+