trusty (4) hunspell.4.gz

Provided by: libhunspell-dev_1.3.2-6ubuntu2.1_amd64 bug

NAME

       hunspell - format of Hunspell dictionaries and affix files

DESCRIPTION

       Hunspell(1) Hunspell requires two files to define the way a language is being spell checked: a dictionary
       file containing words and applicable flags, and an affix file that specifies how these flags wil controll
       spell checking.  An optional file is the personal dictionary file.

Dictionary file

       A  dictionary  file  (*.dic)  contains a list of words, one per line.  The first line of the dictionaries
       (except personal dictionaries) contains the approximate word count (for optimal hash memory  size).  Each
       word  may  optionally  be  followed  by  a  slash  ("/") and one or more flags, which represents the word
       attributes, for example affixes.

       Note: Dictionary words can contain also slashes when escaped like  "" syntax.

Personal dictionary file

       Personal dictionaries are simple word lists. Asterisk at the first character position signs  prohibition.
       A second word separated by a slash sets the affixation.

              foo
              Foo/Simpson
              *bar

       In  this example, "foo" and "Foo" are personal words, plus Foo will be recognized with affixes of Simpson
       (Foo's etc.) and bar is a forbidden word.

Short example

       Dictionary file:

              3
              hello
              try/B
              work/AB

       The flags B and A specify attributes of these words.

       Affix file:

              SET UTF-8
              TRY esianrtolcdugmphbyfvkwzESIANRTOLCDUGMPHBYFVKWZ'

              REP 2
              REP f ph
              REP ph f

              PFX A Y 1
              PFX A 0 re .

              SFX B Y 2
              SFX B 0 ed [^y]
              SFX B y ied y

       In the affix file, prefix A and suffix B have been defined.  Flag A  defines  a  `re-'  prefix.  Class  B
       defines two `-ed' suffixes. First B suffix can be added to a word if the last character of the word isn't
       `y'.  Second suffix can be added to the words terminated with an `y'.

       All accepted words with this dictionary and affix  combination  are:  "hello",  "try",  "tried",  "work",
       "worked", "rework", "reworked".

AFFIX FILE GENERAL OPTIONS

       Hunspell source distribution contains more than 80 examples for option usage.

       SET encoding
              Set  character  encoding  of  words and morphemes in affix and dictionary files.  Possible values:
              UTF-8, ISO8859-1 - ISO8859-10, ISO8859-13 - ISO8859-15, KOI8-R, KOI8-U,  microsoft-cp1251,  ISCII-
              DEVANAGARI.

              SET UTF-8

       FLAG value
              Set flag type. Default type is the extended ASCII (8-bit) character.  `UTF-8' parameter sets UTF-8
              encoded Unicode character flags.  The `long' value sets the double extended ASCII  character  flag
              type,  the `num' sets the decimal number flag type. Decimal flags numbered from 1 to 65000, and in
              flag fields are separated by comma.  BUG: UTF-8 flag type doesn't work on ARM platform.

              FLAG long

       COMPLEXPREFIXES
              Set twofold prefix stripping  (but  single  suffix  stripping)  eg.  for  morphologically  complex
              languages with right-to-left writing system.

       LANG langcode
              Set  language  code for language specific functions of Hunspell. Use it to activate special casing
              of Azeri (LANG az) and Turkish (LANG tr).

       IGNORE characters
              Sets characters to ignore  dictionary  words,  affixes  and  input  words.   Useful  for  optional
              characters,  as  Arabic  (harakat)  or  Hebrew (niqqud) diacritical marks (see tests/ignore.* test
              dictionary in Hunspell distribution).

       AF number_of_flag_vector_aliases

       AF flag_vector
              Hunspell can substitute affix flag sets with ordinal numbers in affix  rules  (alias  compression,
              see makealias tool). First example with alias compression:

              3
              hello
              try/1
              work/2

       AF definitions in the affix file:

              AF 2
              AF A
              AF AB

       It is equivalent of the following dic file:

              3
              hello
              try/A
              work/AB

       See also tests/alias* examples of the source distribution.

       Note I: If affix file contains the FLAG parameter, define it before the AF definitions.

       Note II: Use makealias utility in Hunspell distribution to compress aff and dic files.

       AM number_of_morphological_aliases

       AM morphological_fields
              Hunspell  can  substitute  also  morphological  data  with  ordinal  numbers in affix rules (alias
              compression).  See tests/alias* examples.

AFFIX FILE OPTIONS FOR SUGGESTION

       Suggestion parameters can optimize the default n-gram (similarity search in the dictionary words based on
       the  common  1,  2,  3,  4-character  length  common  character-sequences),  character  swap and deletion
       suggestions of Hunspell.  REP is suggested to fix the typical and especially bad language specific  bugs,
       because  the  REP  suggestions  have the highest priority in the suggestion list.  PHONE is for languages
       with not pronunciation based orthography.

       KEY characters_separated_by_vertical_line_optionally
              Hunspell searches and suggests words with one different  character  replaced  by  a  neighbor  KEY
              character. Not neighbor characters in KEY string separated by vertical line characters.  Suggested
              KEY parameters for QWERTY and Dvorak keyboard layouts:

              KEY qwertyuiop|asdfghjkl|zxcvbnm
              KEY pyfgcrl|aeouidhtns|qjkxbmwvz

       Using the first QWERTY layout, Hunspell suggests "nude" and "node" for "*nide". A character may have more
       neighbors, too:

              KEY qwertzuop|yxcvbnm|qaw|say|wse|dsx|sy|edr|fdc|dx|rft|gfv|fc|tgz|hgb|gv|zhu|jhn|hb|uji|kjm|jn|iko|lkm

       TRY characters
              Hunspell  can  suggest  right  word  forms,  when  they  differ from the bad input word by one TRY
              character. The parameter of TRY is case sensitive.

       NOSUGGEST flag
              Words signed with NOSUGGEST flag are not suggested (but  still  accepted  when  typed  correctly).
              Proposed flag for vulgar and obscene words (see also SUBSTANDARD).

       MAXCPDSUGS num
              Set  max.  number  of  suggested  compound  words  generated  by compound rules. The number of the
              suggested compound words may be greater from the same 1-character distance type.

       MAXNGRAMSUGS num
              Set max. number of n-gram suggestions. Value 0 switches  off  the  n-gram  suggestions  (see  also
              MAXDIFF).

       MAXDIFF [0-10]
              Set  the  similarity  factor for the n-gram based suggestions (5 = default value; 0 = fewer n-gram
              suggestions, but min. 1; 10 = MAXNGRAMSUGS n-gram suggestions).

       ONLYMAXDIFF
              Remove all bad n-gram suggestions (default mode keeps one, see MAXDIFF).

       NOSPLITSUGS
              Disable word suggestions with spaces.

       SUGSWITHDOTS
              Add dot(s)  to  suggestions,  if  input  word  terminates  in  dot(s).   (Not  for  OpenOffice.org
              dictionaries, because OpenOffice.org has an automatic dot expansion mechanism.)

       REP number_of_replacement_definitions

       REP what replacement
              This table specifies modifications to try first.  First REP is the header of this table and one or
              more REP data line are following it.  With this table, Hunspell can suggest the  right  forms  for
              the typical spelling mistakes when the incorrect form differs by more than 1 letter from the right
              form.  The search string supports the regex boundary signs (^ and  $).   For  example  a  possible
              English replacement table definition to handle misspelled consonants:

              REP 5
              REP f ph
              REP ph f
              REP tion$ shun
              REP ^cooccurr co-occurr
              REP ^alot$ a_lot

       Note  I:  It's  very useful to define replacements for the most typical one-character mistakes, too: with
       REP you can add higher priority to a subset of the TRY suggestions (suggestion list begins with  the  REP
       suggestions).

       Note II: Suggesting separated words, specify spaces with underlines:

              REP 1
              REP onetwothree one_two_three

       Note  III:  Replacement  table  can  be  used  for  a  stricter  compound  word  checking with the option
       CHECKCOMPOUNDREP.

       MAP number_of_map_definitions

       MAP string_of_related_chars_or_parenthesized_character_sequences
              We can define language-dependent information on characters and character sequences that should  be
              considered  related  (i.e.  nearer than other chars not in the set) in the affix file (.aff)  by a
              map table.  With this table, Hunspell can suggest the right forms  for  words,  which  incorrectly
              choose the wrong letter or letter groups from a related set more than once in a word (see REP).

              For  example  a possible mapping could be for the German umlauted ü versus the regular u; the word
              Frühstück really should be written with umlauted u's and not regular ones

              MAP 1
              MAP uü

       Use parenthesized groups for character sequences (eg. for composed Unicode characters):

              MAP 3
              MAP ß(ss)  (character sequence)
              MAP fi(fi)  ("fi" compatibility characters for Unicode fi ligature)
              MAP (ọ́)o   (composed Unicode character: ó with bottom dot)

       PHONE number_of_phone_definitions

       PHONE what replacement
              PHONE uses a table-driven phonetic transcription algorithm borrowed from Aspell. It is useful  for
              languages  with  not  pronunciation  based orthography. You can add a full alphabet conversion and
              other  rules  for  conversion  of  special  letter  sequences.  For  detailed  documentation   see
              http://aspell.net/man-html/Phonetic-Code.html.   Note:  Multibyte UTF-8 characters have not worked
              with bracket expression yet. Dash expression has signed bytes and not UTF-8 characters yet.

       WARN flag
              This flag is for rare words, wich are also often spelling mistakes, see option -r of command  line
              Hunspell and FORBIDWARN.

       FORBIDWARN
              Words with flag WARN aren't accepted by the spell checker using this parameter.

OPTIONS FOR COMPOUNDING

       BREAK number_of_break_definitions

       BREAK character_or_character_sequence
              Define  new  break  points  for  breaking words and checking word parts separately. Use ^ and $ to
              delete characters at end and start of the word. Rationale: useful  for  compounding  with  joining
              character  or  strings  (for  example,  hyphen  in  English  and  German  or  hyphen and n-dash in
              Hungarian). Dashes are often bad break points for tokenization, because compounds with dashes  may
              contain  not  valid  parts,  too.)   With  BREAK, Hunspell can check both side of these compounds,
              breaking the words at dashes and n-dashes:

              BREAK 2
              BREAK -
              BREAK --    # n-dash

       Breaking are recursive, so foo-bar, bar-foo and foo-foo--bar-bar would be  valid  compounds.   Note:  The
       default word break of Hunspell is equivalent of the following BREAK definition:

              BREAK 3
              BREAK -
              BREAK ^-
              BREAK -$

       Hunspell doesn't accept the "-word" and "word-" forms by this BREAK definition:

              BREAK 1
              BREAK -

       Switching off the default values:

              BREAK 0

       Note  II:  COMPOUNDRULE is better for handling dashes and other  compound joining characters or character
       strings. Use BREAK, if you want to check words with dashes or other joining characters and  there  is  no
       time  or  possibility to describe precise compound rules with COMPOUNDRULE (COMPOUNDRULE handles only the
       suffixation of the last word part of a compound word).

       Note III: For command line spell checking of words  with  extra  characters,  set  WORDCHARS  parameters:
       WORDCHARS --- (see tests/break.*) example

       COMPOUNDRULE number_of_compound_definitions

       COMPOUNDRULE compound_pattern
              Define custom compound patterns with a regex-like syntax.  The first COMPOUNDRULE is a header with
              the number of the following COMPOUNDRULE definitions. Compound patterns  consist  compound  flags,
              parentheses,  star  and  question  mark  meta  characters. A flag followed by a `*' matches a word
              sequence of 0 or more matches of words signed with this compound flag.  A flag followed by  a  `?'
              matches  a  word  sequence  of  0  or  1  matches  of  a word signed with this compound flag.  See
              tests/compound*.* examples.

              Note: en_US dictionary of OpenOffice.org uses COMPOUNDRULE for ordinal  number  recognition  (1st,
              2nd, 11th, 12th, 22nd, 112th, 1000122nd etc.).

              Note II: In the case of long and numerical flag types use only parenthesized flags: (1500)*(2000)?

              Note  III:  COMPOUNDRULE  flags  work  completely separately from the compounding mechanisme using
              COMPOUNDFLAG, COMPOUNDBEGIN, etc. compound flags. (Use  these  flags  on  different  enhtries  for
              words).

       COMPOUNDMIN num
              Minimum length of words used for compounding.  Default value is 3 letters.

       COMPOUNDFLAG flag
              Words  signed  with  COMPOUNDFLAG  may  be  in  compound  words  (except  when  word  shorter than
              COMPOUNDMIN). Affixes with COMPOUNDFLAG also permits compounding of affixed words.

       COMPOUNDBEGIN flag
              Words signed with COMPOUNDBEGIN (or with a signed affix) may be first elements in compound words.

       COMPOUNDLAST flag
              Words signed with COMPOUNDLAST (or with a signed affix) may be last elements in compound words.

       COMPOUNDMIDDLE flag
              Words signed with COMPOUNDMIDDLE (or with a signed affix)  may  be  middle  elements  in  compound
              words.

       ONLYINCOMPOUND flag
              Suffixes signed with ONLYINCOMPOUND flag may be only inside of compounds (Fuge-elements in German,
              fogemorphemes   in   Swedish).    ONLYINCOMPOUND    flag    works    also    with    words    (see
              tests/onlyincompound.*).  Note: also valuable to flag compounding parts which are not correct as a
              word by itself.

       COMPOUNDPERMITFLAG flag
              Prefixes are allowed at the beginning of compounds, suffixes are allowed at the end  of  compounds
              by default.  Affixes with COMPOUNDPERMITFLAG may be inside of compounds.

       COMPOUNDFORBIDFLAG flag
              Suffixes with this flag forbid compounding of the affixed word.

       COMPOUNDROOT flag
              COMPOUNDROOT  flag  signs  the  compounds  in the dictionary (Now it is used only in the Hungarian
              language specific code).

       COMPOUNDWORDMAX number
              Set maximum word count in a compound word. (Default is unlimited.)

       CHECKCOMPOUNDDUP
              Forbid word duplication in compounds (e.g. foofoo).

       CHECKCOMPOUNDREP
              Forbid compounding, if the (usually bad) compound word may be a  non  compound  word  with  a  REP
              fault. Useful for languages with `compound friendly' orthography.

       CHECKCOMPOUNDCASE
              Forbid upper case characters at word boundaries in compounds.

       CHECKCOMPOUNDTRIPLE
              Forbid  compounding,  if  compound word contains triple repeating letters (e.g. foo|ox or xo|oof).
              Bug: missing  multi-byte  character  support  in  UTF-8  encoding  (works  only  for  7-bit  ASCII
              characters).

       SIMPLIFIEDTRIPLE
              Allow  simplified  2-letter  forms of the compounds forbidden by CHECKCOMPOUNDTRIPLE.  It's useful
              for Swedish and Norwegian (and for the old German orthography: Schiff|fahrt -> Schiffahrt).

       CHECKCOMPOUNDPATTERN number_of_checkcompoundpattern_definitions

       CHECKCOMPOUNDPATTERN endchars[/flag] beginchars[/flag] [replacement]
              Forbid compounding, if the first word in the compound ends with endchars,  and  next  word  begins
              with  beginchars  and  (optionally)  they  have  the  requested  flags.   The optional replacement
              parameter allows simplified compound form.

              The special "endchars" pattern 0 (zero) limits the rule to the unmodified stems (stems  and  stems
              with zero affixes):

              CHECKCOMPOUNDPATTERN 0/x /y

       Note:  COMPOUNDMIN  doesn't  work  correctly  with  the  compound word alternation, so it may need to set
       COMPOUNDMIN to lower value.

       FORCEUCASE flag
              Last word part of a compound with flag FORCEUCASE forces  capitalization  of  the  whole  compound
              word.  Eg.  Dutch  word  "straat"  (street) with FORCEUCASE flags will allowed only in capitalized
              compound forms, according to the Dutch spelling rules for proper names.

       COMPOUNDSYLLABLE max_syllable vowels
              Need for special compounding rules in Hungarian.  First parameter is the maximum syllable  number,
              that  may be in a compound, if words in compounds are more than COMPOUNDWORDMAX.  Second parameter
              is the list of vowels (for calculating syllables).

       SYLLABLENUM flags
              Need for special compounding rules in Hungarian.

AFFIX FILE OPTIONS FOR AFFIX CREATION

       PFX flag cross_product number

       PFX flag stripping prefix [condition [morphological_fields...]]

       SFX flag cross_product number

       SFX flag stripping suffix [condition [morphological_fields...]]
              An affix is either a prefix or a suffix attached to root words to make other words. We can  define
              affix  classes  with arbitrary number affix rules.  Affix classes are signed with affix flags. The
              first line of an affix class definition is the header. The fields of an affix class header:

              (0) Option name (PFX or SFX)

              (1) Flag (name of the affix class)

              (2) Cross product (permission to combine prefixes and suffixes).  Possible values: Y  (yes)  or  N
              (no)

              (3) Line count of the following rules.

              Fields of an affix rules:

              (0) Option name

              (1) Flag

              (2) stripping characters from beginning (at prefix rules) or end (at suffix rules) of the word

              (3) affix (optionally with flags of continuation classes, separated by a slash)

              (4) condition.

              Zero stripping or affix are indicated by zero. Zero condition is indicated by dot.  Condition is a
              simplified, regular expression-like pattern, which must be met before the affix  can  be  applied.
              (Dot  signs  an  arbitrary  character.  Characters  in braces sign an arbitrary character from the
              character subset. Dash hasn't got special meaning, but circumflex (^) next the  first  brace  sets
              the complementer character set.)

              (5) Optional morphological fields separated by spaces or tabulators.

AFFIX FILE OTHER OPTIONS

       CIRCUMFIX flag
              Affixes  signed  with  CIRCUMFIX  flag  may  be  on  a  word when this word also has a prefix with
              CIRCUMFIX flag and vice versa (see circumfix.* test files in the source distribution).

       FORBIDDENWORD flag
              This flag signs forbidden word form. Because affixed forms are also forbidden, we can  subtract  a
              subset  from  set  of  the accepted affixed and compound words.  Note: usefull to forbid erroneous
              words, generated by the compounding mechanism.

       FULLSTRIP
              With FULLSTRIP, affix rules can strip full words, not only one less characters, before adding  the
              affixes,  see  fullstrip.*  test  files in the source distribution).  Note: conditions may be word
              length without FULLSTRIP, too.

       KEEPCASE flag
              Forbid uppercased and capitalized forms of words signed with KEEPCASE flags.  Useful  for  special
              orthographies  (measurements  and  currency often keep their case in uppercased texts) and writing
              systems (e.g. keeping lower case of IPA characters).  Also valuable for words erroneously  written
              in the wrong case.

              Note:  With  CHECKSHARPS  declaration, words with sharp s and KEEPCASE flag may be capitalized and
              uppercased, but  uppercased  forms  of  these  words  may  not  contain  sharp  s,  only  SS.  See
              germancompounding example in the tests directory of the Hunspell distribution.

       ICONV number_of_ICONV_definitions

       ICONV pattern pattern2
              Define  input  conversion  table.   Note:  useful  to convert one type of quote to another one, or
              change ligature.

       OCONV number_of_OCONV_definitions

       OCONV pattern pattern2
              Define output conversion table.

       LEMMA_PRESENT flag
              Deprecated. Use "st:" field instead of LEMMA_PRESENT.

       NEEDAFFIX flag
              This flag signs virtual stems in the dictionary, words only valid when affixed.   Except,  if  the
              dictionary  word  has  a homonym or a zero affix.  NEEDAFFIX works also with prefixes and prefix +
              suffix combinations (see tests/pseudoroot5.*).

       PSEUDOROOT flag
              Deprecated. (Former name of the NEEDAFFIX option.)

       SUBSTANDARD flag
              SUBSTANDARD flag signs affix rules and dictionary words (allomorphs)  not  used  in  morphological
              generation (and in suggestion in the future versions). See also NOSUGGEST.

       WORDCHARS characters
              WORDCHARS extends tokenizer of Hunspell command line interface with additional word character. For
              example, dot, dash, n-dash, numbers, percent sign are word character in Hungarian.

       CHECKSHARPS
              SS letter pair in uppercased (German) words may be upper case sharp s (ß).   Hunspell  can  handle
              this   special   casing   with   the   CHECKSHARPS   declaration   (see  also  KEEPCASE  flag  and
              tests/germancompounding example) in both spelling and suggestion.

Morphological analysis

       Hunspell's dictionary items and affix rules may have optional space or tabulator separated  morphological
       description fields, started with 3-character (two letters and a colon) field IDs:

               word/flags po:noun is:nom

       Example:  We  define  a  simple resource with morphological informations, a derivative suffix (ds:) and a
       part of speech category (po:):

       Affix file:

               SFX X Y 1
               SFX X 0 able . ds:able

       Dictionary file:

               drink/X po:verb

       Test file:

               drink
               drinkable

       Test:

               $ analyze test.aff test.dic test.txt
               > drink
               analyze(drink) = po:verb
               stem(drink) = po:verb
               > drinkable
               analyze(drinkable) = po:verb ds:able
               stem(drinkable) = drinkable

       You can see in the example,  that  the  analyzer  concatenates  the  morphological  fields  in  item  and
       arrangement style.

Optional data fields

       Default morphological and other IDs (used in suggestion, stemming and morphological generation):

       ph:    Alternative   transliteration   for  better  suggestion.   It's  useful  for  words  with  foreign
              pronunciation. (Dictionary based phonetic suggestion.)  For example:

              Marseille ph:maarsayl

       st:    Stem. Optional: default stem is the dictionary item  in  morphological  analysis.  Stem  field  is
              useful  for  virtual  stems  (dictionary  words  with NEEDAFFIX flag) and morphological exceptions
              instead of new, single used morphological rules.

              feet  st:foot  is:plural
              mice  st:mouse is:plural
              teeth st:tooth is:plural

       Word forms with multiple stems need multiple dictionary items:

              lay po:verb st:lie is:past_2
              lay po:verb is:present
              lay po:noun

       al:    Allomorph(s). A dictionary item is the stem of its  allomorphs.   Morphological  generation  needs
              stem, allomorph and affix fields.

              sing al:sang al:sung
              sang st:sing
              sung st:sing

       po:    Part of speech category.

       ds:    Derivational suffix(es).  Stemming doesn't remove derivational suffixes.  Morphological generation
              depends on the order of the suffix fields.

              In affix rules:

              SFX Y Y 1
              SFX Y 0 ly . ds:ly_adj

       In the dictionary:

              ably st:able ds:ly_adj
              able al:ably

       is:    Inflectional suffix(es).  All  inflectional  suffixes  are  removed  by  stemming.   Morphological
              generation depends on the order of the suffix fields.

              feet st:foot is:plural

       ts:    Terminal  suffix(es).   Terminal  suffix  fields  are  inflectional  suffix  fields  "removed"  by
              additional (not terminal) suffixes.

              Useful for zero morphemes and affixes removed by splitting rules.

              work/D ts:present

              SFX D Y 2
              SFX D   0 ed . is:past_1
              SFX D   0 ed . is:past_2

       Typical example of the terminal suffix is the zero morpheme of the nominative case.

       sp:    Surface prefix. Temporary solution for adding prefixes to the stems and generated word forms.  See
              tests/morph.* example.

       pa:    Parts of the compound words. Output fields of morphological analysis for stemming.

       dp:    Planned: derivational prefix.

       ip:    Planned: inflectional prefix.

       tp:    Planned: terminal prefix.

Twofold suffix stripping

       Ispell's  original algorithm strips only one suffix. Hunspell can strip another one yet (or a plus prefix
       in COMPLEXPREFIXES mode).

       The twofold suffix stripping is a significant improvement in handling of immense number of suffixes, that
       characterize agglutinative languages.

       A  second `s' suffix (affix class Y) will be the continuation class of the suffix `able' in the following
       example:

               SFX Y Y 1
               SFX Y 0 s .

               SFX X Y 1
               SFX X 0 able/Y .

       Dictionary file:

               drink/X

       Test file:

               drink
               drinkable
               drinkables

       Test:

               $ hunspell -m -d test <test.txt
               drink st:drink
               drinkable st:drink fl:X
               drinkables st:drink fl:X fl:Y

       Theoretically with the twofold suffix stripping needs only the square root of the number of suffix rules,
       compared  with  a  Hunspell  implementation.  In  our  practice,  we  could have elaborated the Hungarian
       inflectional morphology with twofold suffix stripping.

Extended affix classes

       Hunspell can handle more than 65000 affix classes.  There are three new syntax for giving flags in  affix
       and dictionary files.

       FLAG long command sets 2-character flags:

                FLAG long
                SFX Y1 Y 1
                SFX Y1 0 s 1

       Dictionary record with the Y1, Z3, F? flags:

                foo/Y1Z3F?

       FLAG num command sets numerical flags separated by comma:

                FLAG num
                SFX 65000 Y 1
                SFX 65000 0 s 1

       Dictionary example:

                foo/65000,12,2756

       The third one is the Unicode character flags.

Homonyms

       Hunspell's dictionary can contain repeating elements that are homonyms:

               work/A    po:verb
               work/B    po:noun

       An affix file:

               SFX A Y 1
               SFX A 0 s . sf:sg3

               SFX B Y 1
               SFX B 0 s . is:plur

       Test file:

               works

       Test:

               $ hunspell -d test -m <testwords
               work st:work po:verb is:sg3
               work st:work po:noun is:plur

       This feature also gives a way to forbid illegal prefix/suffix combinations.

Prefix--suffix dependencies

       An  interesting side-effect of multi-step stripping is, that the appropriate treatment of circumfixes now
       comes for free.  For instance, in Hungarian, superlatives are formed by simultaneous prefixation of  leg-
       and suffixation of -bb to the adjective base.  A problem with the one-level architecture is that there is
       no way to render lexical licensing of particular prefixes  and  suffixes  interdependent,  and  therefore
       incorrect  forms  are  recognized  as  valid,  i.e.  *legvén = leg + vén `old'. Until the introduction of
       clusters, a special treatment of the superlative had to be hardwired in the earlier HunSpell  code.  This
       may  have  been  legitimate  for  a single case, but in fact prefix--suffix dependences are ubiquitous in
       category-changing derivational patterns (cf. English payable,  non-payable  but  *non-pay  or  drinkable,
       undrinkable  but *undrink). In simple words, here, the prefix un- is legitimate only if the base drink is
       suffixed with -able. If both these patters are handled by on-line affix rules and affix rules are checked
       against  the  base only, there is no way to express this dependency and the system will necessarily over-
       or undergenerate.

       In next example, suffix class R have got a prefix `continuation' class (class P).

              PFX P Y 1
              PFX P   0 un . [prefix_un]+

              SFX S Y 1
              SFX S   0 s . +PL

              SFX Q Y 1
              SFX Q   0 s . +3SGV

              SFX R Y 1
              SFX R   0 able/PS . +DER_V_ADJ_ABLE

       Dictionary:

              2
              drink/RQ  [verb]
              drink/S   [noun]

       Morphological analysis:

              > drink
              drink[verb]
              drink[noun]
              > drinks
              drink[verb]+3SGV
              drink[noun]+PL
              > drinkable
              drink[verb]+DER_V_ADJ_ABLE
              > drinkables
              drink[verb]+DER_V_ADJ_ABLE+PL
              > undrinkable
              [prefix_un]+drink[verb]+DER_V_ADJ_ABLE
              > undrinkables
              [prefix_un]+drink[verb]+DER_V_ADJ_ABLE+PL
              > undrink
              Unknown word.
              > undrinks
              Unknown word.

Circumfix

       Conditional affixes implemented by a continuation  class  are  not  enough  for  circumfixes,  because  a
       circumfix is one affix in morphology. We also need CIRCUMFIX option for correct morphological analysis.

              # circumfixes: ~ obligate prefix/suffix combinations
              # superlative in Hungarian: leg- (prefix) AND -bb (suffix)
              # nagy, nagyobb, legnagyobb, legeslegnagyobb
              # (great, greater, greatest, most greatest)

              CIRCUMFIX X

              PFX A Y 1
              PFX A 0 leg/X .

              PFX B Y 1
              PFX B 0 legesleg/X .

              SFX C Y 3
              SFX C 0 obb . +COMPARATIVE
              SFX C 0 obb/AX . +SUPERLATIVE
              SFX C 0 obb/BX . +SUPERSUPERLATIVE

       Dictionary:

              1
              nagy/C    [MN]

       Analysis:

              > nagy
              nagy[MN]
              > nagyobb
              nagy[MN]+COMPARATIVE
              > legnagyobb
              nagy[MN]+SUPERLATIVE
              > legeslegnagyobb
              nagy[MN]+SUPERSUPERLATIVE

Compounds

       Allowing  free  compounding  yields  decrease  in  precision  of recognition, not to mention stemming and
       morphological analysis.  Although lexical switches are introduced to  license  compounding  of  bases  by
       Ispell, this proves not to be restrictive enough. For example:

              # affix file
              COMPOUNDFLAG X

              2
              foo/X
              bar/X

       With this resource, foobar and barfoo also are accepted words.

       This  has  been  improved  upon  with  the introduction of direction-sensitive compounding, i.e., lexical
       features can specify separately whether a  base  can  occur  as  leftmost  or  rightmost  constituent  in
       compounds.   This, however, is still insufficient to handle the intricate patterns of compounding, not to
       mention idiosyncratic (and language specific) norms of hyphenation.

       The Hunspell algorithm currently allows any  affixed  form  of  words,  which  are  lexically  marked  as
       potential  members  of compounds. Hunspell improved this, and its recursive compound checking rules makes
       it possible to implement the intricate spelling conventions of Hungarian compounds.  For  example,  using
       COMPOUNDWORDMAX,  COMPOUNDSYLLABLE, COMPOUNDROOT, SYLLABLENUM options can be set the noteworthy Hungarian
       `6-3' rule.  Further example  in  Hungarian,  derivate  suffixes  often  modify  compounding  properties.
       Hunspell allows the compounding flags on the affixes, and there are two special flags (COMPOUNDPERMITFLAG
       and (COMPOUNDFORBIDFLAG) to permit or prohibit compounding of the derivations.

       Suffixes with this flag forbid compounding of the affixed word.

       We also need several Hunspell features for handling German compounding:

              # German compounding

              # set language to handle special casing of German sharp s

              LANG de_DE

              # compound flags

              COMPOUNDBEGIN U
              COMPOUNDMIDDLE V
              COMPOUNDEND W

              # Prefixes are allowed at the beginning of compounds,
              # suffixes are allowed at the end of compounds by default:
              # (prefix)?(root)+(affix)?
              # Affixes with COMPOUNDPERMITFLAG may be inside of compounds.
              COMPOUNDPERMITFLAG P

              # for German fogemorphemes (Fuge-element)
              # Hint: ONLYINCOMPOUND is not required everywhere, but the
              # checking will be a little faster with it.

              ONLYINCOMPOUND X

              # forbid uppercase characters at compound word bounds
              CHECKCOMPOUNDCASE

              # for handling Fuge-elements with dashes (Arbeits-)
              # dash will be a special word

              COMPOUNDMIN 1
              WORDCHARS -

              # compound settings and fogemorpheme for `Arbeit'

              SFX A Y 3
              SFX A 0 s/UPX .
              SFX A 0 s/VPDX .
              SFX A 0 0/WXD .

              SFX B Y 2
              SFX B 0 0/UPX .
              SFX B 0 0/VWXDP .

              # a suffix for `Computer'

              SFX C Y 1
              SFX C 0 n/WD .

              # for forbid exceptions (*Arbeitsnehmer)

              FORBIDDENWORD Z

              # dash prefix for compounds with dash (Arbeits-Computer)

              PFX - Y 1
              PFX - 0 -/P .

              # decapitalizing prefix
              # circumfix for positioning in compounds

              PFX D Y 29
              PFX D A a/PX A
              PFX D Ä ä/PX Ä
               .
               .
              PFX D Y y/PX Y
              PFX D Z z/PX Z

       Example dictionary:

              4
              Arbeit/A-
              Computer/BC-
              -/W
              Arbeitsnehmer/Z

       Accepted compound compound words with the previous resource:

              Computer
              Computern
              Arbeit
              Arbeits-
              Computerarbeit
              Computerarbeits-
              Arbeitscomputer
              Arbeitscomputern
              Computerarbeitscomputer
              Computerarbeitscomputern
              Arbeitscomputerarbeit
              Computerarbeits-Computer
              Computerarbeits-Computern

       Not accepted compoundings:

              computer
              arbeit
              Arbeits
              arbeits
              ComputerArbeit
              ComputerArbeits
              Arbeitcomputer
              ArbeitsComputer
              Computerarbeitcomputer
              ComputerArbeitcomputer
              ComputerArbeitscomputer
              Arbeitscomputerarbeits
              Computerarbeits-computer
              Arbeitsnehmer

       This solution is still not ideal, however, and will be  replaced  by  a  pattern-based  compound-checking
       algorithm  which is closely integrated with input buffer tokenization. Patterns describing compounds come
       as a separate input resource that can refer to high-level  properties  of  constituent  parts  (e.g.  the
       number of syllables, affix flags, and containment of hyphens). The patterns are matched against potential
       segmentations of compounds to assess wellformedness.

Unicode character encoding

       Both Ispell and Myspell use 8-bit ASCII character encoding, which is a major deficiency when it comes  to
       scalability.   Although  a  language  like  Hungarian has a standard ASCII character set (ISO 8859-2), it
       fails to allow a full implementation of Hungarian  orthographic  conventions.   For  instance,  the  '--'
       symbol  (n-dash) is missing from this character set contrary to the fact that it is not only the official
       symbol to delimit parenthetic clauses in the language, but it can be in compound words as a special 'big'
       hyphen.

       MySpell has got some 8-bit encoding tables, but there are languages without standard 8-bit encoding, too.
       For example, a lot of African languages have non-latin or extended latin characters.

       Similarly, using the original spelling of certain foreign names like Ångström or Molière is encouraged by
       the  Hungarian  spelling  norm,  and,  since characters 'Å' and 'è' are not part of ISO 8859-2, when they
       combine with inflections containing characters only in ISO 8859-2 (like elative -ből,  allative  -től  or
       delative  -ről  with double acute), these result in words (like Ångströmről or Molière-től.) that can not
       be encoded using any single ASCII encoding scheme.

       The problems raised in relation to 8-bit ASCII encoding  have  long  been  recognized  by  proponents  of
       Unicode. It is clear that trading efficiency for encoding-independence has its advantages when it comes a
       truly multi-lingual application. There is implemented a memory and time  efficient  Unicode  handling  in
       Hunspell.  In  non-UTF-8  character  encodings  Hunspell  works with the original 8-bit strings. In UTF-8
       encoding, affixes and words are stored in UTF-8, during the analysis are handled in mostly  UTF-8,  under
       condition  checking and suggestion are converted to UTF-16. Unicode text analysis and spell checking have
       a minimal (0-20%) time overhead and minimal or reasonable memory overhead depends from the language  (its
       UTF-8 encoding and affixation).

Conversion of aspell dictionaries

       Aspell dictionaries can be easily converted into hunspell. Conversion steps:

       dictionary (xx.cwl -> xx.wl):

       preunzip xx.cwl
       wc -l < xx.wl > xx.dic
       cat xx.wl >> xx.dic

       affix file

       If the affix file exists, copy it:
       cp xx_affix.dat xx.aff
       If not, create it with the suitable character encoding (see xx.dat)
       echo "SET ISO8859-x" > xx.aff
       or
       echo "SET UTF-8" > xx.aff

       It's  useful  to  add a TRY option with the characters of the dictionary with frequency order to set edit
       distance suggestions:
       echo "TRY qwertzuiopasdfghjklyxcvbnmQWERTZUIOPASDFGHJKLYXCVBNM" >>xx.aff

Conversion of aspell dictionaries

       Aspell dictionaries can be easily converted into hunspell. Conversion steps:

       dictionary (xx.cwl -> xx.wl):

       preunzip xx.cwl
       wc -l < xx.wl > xx.dic
       cat xx.wl >> xx.dic

       affix file

       If the affix file exists, copy it:
       cp xx_affix.dat xx.aff
       If not, create it with the suitable character encoding (see xx.dat)
       echo "SET ISO8859-x" > xx.aff
       or
       echo "SET UTF-8" > xx.aff

       It's useful to add a TRY option with the characters of the dictionary with frequency order  to  set  edit
       distance suggestions:
       echo "TRY qwertzuiopasdfghjklyxcvbnmQWERTZUIOPASDFGHJKLYXCVBNM" >>xx.aff

SEE ALSO

       hunspell (1), ispell (1), ispell (4)

                                                   2011-02-16                                        hunspell(4)