The TGrep language by Richard Pito
formulates queries as patterns that consist of expressions
to match tree nodes and relationships defining links or negated links to other tree nodes.
Nodes of searched trees are matched either with
simple character strings or regular expressions (see sections 1).
A complex expression consists of a node expression followed by relationships,
as presented in section 2.
Possible relationships are illustrated in section 3.
When you compose a search expression in the box provided,
if the search expression uses TGrep-lite syntax,
the interface will recognize that and interpret the expression accordingly.
If the expression is well-formed but there are no matches in the corpus,
the screen shows no change after the “Submit” button is pressed.
If the expression is not well-formed, the warning
“Not a valid TGrep-lite expression.”
appears.
In the result page, if you check the “reveal” box and resubmit,
a translation of the TGrep-lite expression into XPath syntax is displayed.
This allows you to check whether the expression you have composed reflects the search that is intended.
The TGrep functionality available here is referred to as “TGrep-lite”.
This is less expressive than the full TGrep language implemented in the original TGrep program.
In particular,
the expression of relationships between nodes is limited to the relations detailed in section 3.
TGrep-lite is especially weak when compared to enhanced TGrep languages
available with TGrep2
and Tregex implementations,
notably,
missing the ability to express disjunctions of relations.
TGrep-lite will also exhibit behaviour distinct from what is expected from TGrep
with regards to how nodes are specified
(described in section 1).
Despite these mentioned limitations,
TGrep-lite is the easiest and most accessible way to search the corpus using this on-line interface,
and it is a powerful search language.
TGrep-lite works by rewriting expressions of a modified TGrep language into XPath queries over a database of XML encoded trees.
The formatting of the XML
requires
that the rewrite to XPath distinguishes
three different “node” kinds expressed with TGrep-lite node patterns:
word nodes,
pre-terminal nodes (that provide information about the word, e.g., the word is a zero element), and
part-of-speech/phrase-level nodes.
The wild card (“__”) is exceptional in not needing to distinguish its node kind,
since it will match all nodes.
A simple constant string,
such as “abc”, etc.,
will match word nodes that are the unique string abc.
The expression of all other node patterns
occurs as the statement of a regular expression
with deliminators to
determine the kind of the node searched.
Specifically:
a regular expression indicated by surrounding slashes (“/”), such as “/ab/”, will search for word nodes,
a regular expression indicated by surrounding curly brackets (“{”, “}”), such as “{AB}”, will search for pre-terminal nodes, and
a regular expression indicated by surrounding square brackets (“[”, “]”), such as “[AB]”, will search for part-of-speech/phrase-level nodes.
If a simple constant string or deliminated regular expression begins with “!”,
the matching process will be complemented. That is, matches will turn into non-matches,
and vice-versa.
For example, “!abc” will match all words that are not abc,
and “![^NP] will match any part-of-speech or phrase-level node that does not start with NP.
Specified as a string,
a regular expression matches a node if there is a part of the node that is matched.
For example, “[IP]” matches IP-MAT, IP-ADV, etc.
The caret (“^”) anchors the regular expression to the beginning of a matched node,
while a dollar sign (“$”) as the last character will anchor the regular expression
to the end of a matched node.
Use of both the caret and dollar-sign in “[^NP$]” constrains the match to only NP.
A word boundary can be stated with “\b”.
Thus,
while “[^NP]” will match both NP-SBJ and NPR,
“[^NP\b]” will match only NP-SBJ.
Disjunction can be expressed with the pipe (“|”),
and regular expression elements can be grouped with round brackets,
such that “[^NP-(SBJ|OB1)]” will find nodes that start with either NP-SBJ or NP-OB1.
Note that the on-line interface is case insensitive
when the node is identified as being either a pre-terminal or part-of-speech/phrase-level node,
while being case sensitive for word (terminal) nodes.
TGrep-lite expressions are composed of a node pattern followed by the relationships the node pattern participates in.
Because word information
serves as content of the same node under the XML encoding
as pre-terminal node information,
it becomes necessary if you wish to match the combination of a particular word with a particular pre-terminal node
that the “==” (equals) relation serves to connect this information about the same underlying node.
For example,
the following will find instances of words that contain “tuti” with the “PHON” pre-terminal tag.
The following example,
will match an IP node which immediately dominates a PP node and which dominates an IP node.
Note the parenthesis to ensure that the second relationship “<< [IP]” refers to the first IP and not to the PP.
As another example,
will match an IP which immediately dominates a PP which in turn dominates some IP.
The first node in a pattern or the first node following a left parenthesis is a “master” node which is related to the relationships to its right. Thus, a TGrep-lite pattern consists of a master node for the entire query followed by a series of relationships to other nodes that can themselves with parenthesis form master nodes with relationships to yet other nodes. In the first example above only the first [IP] is a master node, while in the second example both the first [IP] and the [PP] are master nodes.
Relationships define connections between the master node (being defined) and other nodes. There is a complete pairing of forward and backward links, allowing for flexibility in choosing what is the master node. Notable relationships are:
A << B A dominates (is an ancestor of) B
A >> B A is dominated by (is a descendant of) B
A < B A immediately dominates (is the parent of) B
A > B A is immediately dominated by (is the child of) B
A .. B A precedes B
A ,, B A follows B
A . B A immediately precedes B
A , B A immediately follows B
A $ B A is a sister of and not equal to B
A $.. B A is a sister of and precedes B
A $,, B A is a sister of and follows B
A $. B A is a sister of and immediately precedes B
A $, B A is a sister of and immediately follows B
A $, B A is a sister of and immediately follows B
A == B A and B are the same node
A <<, B B is a leftmost descendant of A
A <<- B B is a rightmost descendant of A
A >>, B A is a leftmost descendant of B
A >>- B A is a rightmost descendant of B
A <1 B B is the 1st child of A
A >1 B A is the 1st child of B
A <-1 B B is the last child of A
A >-1 B A is the last child of B
A <, B B is the first child of A (synonymous with A <1 B)
A >, B A is the first child of B (synonymous with A >1 B)
A <- B B is the last child of A (also synonymous with A <-1 B)
A >- B A is the last child of B (also synonymous with A >-1 B)
A <: B B is the only child of A
A >: B A is the only child of B
A <<: B A dominates B via an unbroken chain (length > 0) of unary branches
A >>: B A is dominated by B via an unbroken chain (length > 0) of unary branches
The following presents pictures grouping some of the above relationships as forward and backward links:
C << __ (dominates, is an ancestor of)
__ >> C (is dominated by, is a descendant of)
E >> __ (is dominated by, is a descendant of)
__ << E (dominates, is an ancestor of)
C > __ (immediately dominates, is the parent of)
__ < C (is immediately dominated by, is the child of)
TGrep-lite returns the match for the left-most element in the search pattern. The following pattern matches PPs that are immediately dominated by an IP that dominates an IP:
TGrep-lite search results
Search results are listed in groups of up to twenty five entries,
each with highlighted portions corresponding to the focus of the query.
Immediately following each entry is a link to the tree for that entry in the form of the ID number of that entry.
Following the link
opens a tree view for the result,
with highlighted nodes corresponding to the focus of the search.
When appropriate,
there is a down arrow to click for moving to the next twenty five results,
and an up arrow for moving back.
In addition,
there is an open text area that contains the pattern for the search.
This gives the opportunity to see and also edit the search query.
Clicking the “Submit” button re-submits the possibly edited search.
At the page end,
there is the option to
download results for searches with results of 2000 items or less.
There are three possible forms in which search results can be downloaded:
basic text format, bracket format, and Alpino XML format.
All formats include the text and ID number of each entry.
Bracket format and Alpino XML format include all the syntactic information encoded for each entry.
Each line of text with the “basic text format” is a tab separated numbered entry,
and the number of the last entry is equal to the number of results for the search.
* kake maku mo * aya ni kasikwo si * pudipara no * miyakwo simimi ni * pito pa si mo * mitite aredomo * kimi pa si mo * opo ku imase do * yuki mukapu * tosi no wo naga ku * tukape ko si * kimi no mikadwo wo * ame no goto * apugite mitutu * kasikwo kyedo * omopi tanomite * itu si ka mo * pitara si masite * moti dukwi no * tatapasi kye mu to * wa ga omopu * mi kwo no mikoto pa * paru sareba * uwe tukwi ga upe no * topo tu pito * matu no sita di yu * nobora site * kuni mi aswobasi * nagatukwi no * sigure no aki pa * opo tono no * migiri simimi ni * tuyu opite * nabik yeru pagwi wo * tama ta suki * kakete sinwopa si * mi yuki puru * puyu no asita pa * sasi yanagwi * ne pari adusa wo * opomi te ni * tora si tamapite * aswobasi si * wa ga opo kimi wo * kasumi tatu * paru no pi kurasi * maswo kagami * miredo aka neba * yorodu yo ni * kaku si moga mo to * opo bune no * tanom yeru toki ni * oyodure ni * me ka mo matwop yeru * opo tono wo * purisake mireba * sirwo tape ni * kazari maturite * utipi sasu * miya no toneri pa * tape no po no * asa ginu k yereba * ime kamo * ututu kamo to * kumori ywo no * matwop yeru potwo ni * asamoyosi * kwinope no miti yu * tunwosapapu * ipare wo mitutu * kamu paburi * paburi matureba * yuku miti no * taduki wo sira ni * omopedomo * sirusi wo na mi * nagekedomo * oku ka wo na mi * opomi swode * yuki pure si matu wo * koto twopa nu * kwi ni pa aredomo * ara tama no * tatu tukwi goto ni * ama no para * purisake mi tutu * tama ta suki * kakete sinwopa na * kasikwo karedomo MYS.13.3324b
* kake maku mo * aya ni kasikwo si * pudipara no * miyakwo simimi ni * pito pa si mo * mitite aredomo * kimi pa si mo * opo ku imase do * yuki mukapu * tosi no wo naga ku * tukape ko si * kimi no mikadwo wo * ame no goto * apugite mitutu * kasikwo kyedo * omopi tanomite * itu si ka mo * pitara si masite * moti dukwi no * tatapasi kye mu to * wa ga omopu * mi kwo no mikoto pa * paru sareba * uwe tukwi ga upe no * topo tu pito * matu no sita di yu * nobora site * kuni mi aswobasi * nagatukwi no * sigure no aki pa * opo tono no * migiri simimi ni * tuyu opite * nabik yeru pagwi wo * tama ta suki * kakete sinwopa si * mi yuki puru * puyu no asita pa * sasi yanagwi * ne pari adusa wo * opomi te ni * tora si tamapite * aswobasi si * wa ga opo kimi wo * kasumi tatu * paru no pi gurasi * maswo kagami * miredo aka neba * yorodu yo ni * kaku si moga mo to * opo bune no * tanom yeru toki ni * oyodure ni * me ka mo matwop yeru * opo tono wo * purisake mireba * sirwo tape ni * kazari maturite * utipi sasu * miya no toneri mo * tape no po no * asa ginu k yereba * ime kamo * ututu kamo to * kumori ywo no * matwop yeru potwo ni * asamoyosi * kwinope no miti yu * tunwosapapu * ipare wo mitutu * kamu paburi * paburi matureba * yuku miti no * taduki wo sira ni * omopedomo * sirusi wo na mi * nagekedomo * oku ka wo na mi * opomi swode * yuki pure si matu wo * koto twopa nu * kwi ni pa aredomo * ara tama no * tatu tukwi goto ni * ama no para * purisake mi tutu * tama ta suki * kakete sinwopa na * kasikwo karedomo MYS.13.3324a
* ame tuti no * pazime no toki * pisakata no * ama no kapara ni * ya po yorodu * ti yorodu kamwi no * kamu tudwopi * tudwopi imasite * kamu pakari * pakari si toki ni * ama tera su * pirumye no mikoto * ame woba * sira si myesu to * asi para no * midu po no kuni wo * ame tuti no * yoriapi no kipami * sira si myesu * kamwi no mikoto to * ama kumo no * ya pye kaki wakite * kamu kudasi * imase maturi si * taka tera su * pi no mi kwo pa * tobu tori no * kiywomi no miya ni * kamu nagara * putwo siki masite * sumyeroki no * siki masu kuni to * ama no para * ipa two wo piraki * kamu agari * agari imasi nu * wa go opo kimi * mi kwo no mikoto no * ame no sita * sira si myesi se ba * paru pana no * taputwo kara mu to * moti dukwi no * tata pasi kye mu to * ame no sita * yomo no pito no * opo bune no * omopi tanomite * ama tu midu * apugite matu ni * ika sama ni * omoposi myese ka * ture mo na ki * mayumi no woka ni * miya basira * putwo siki imasi * mi ara ka wo * taka siri masite * asa gotoni * mi koto twopa sa nu * pi tukwi no * mane ku nari nuru * soko yuwe ni * mi kwo no miya pito * yuku pye sira zu mo MYS.2.167a
* ame tuti no * pazime no toki * pisakata no * ama no kapara ni * ya po yorodu * ti yorodu kamwi no * kamu tudwopi * tudwopi imasi * kamu pakari * pakari si toki ni * sasi noboru * pirumye no mikoto * ame woba * sira si myesu to * asi para no * midu po no kuni wo * ame tuti no * yoriapi no kipami * sira si myesu * kamwi no mikoto to * ama kumo no * ya pye kumo wakite * kamu kudasi * imase maturi si * taka tera su * pi no mi kwo pa * tobu tori no * kiywomi no miya ni * kamu nagara * putwo siki masite * sumyeroki no * siki masu kuni to * ama no para * ipa two wo piraki * kamu nobori * imasi ni sikaba * wa go opo kimi * mi kwo no mikoto no * ame no sita * sira si myesi se ba * paru pana no * taputwo kara mu to * moti dukwi no * tata pasi kye mu to * wosu kuni * yomo no pito no * opo bune no * omopi tanomite * ama tu midu * apugite matu ni * ika sama ni * omoposi myese ka * ture mo na ki * mayumi no woka ni * miya basira * putwo siki imasi * mi ara ka wo * taka siri masite * asa gotoni * mi koto twopa sa nu * pi tukwi no * mane ku nari nuru * sasutake no * mi kwo no miya pito * yuku pye sira ni su MYS.2.167b