Grammar Engineering with LKB and the LinGO Grammar Matrix: Frequently Asked Questions

This is a collection of frequently asked questions related to using the LKB and the Grammar Matrix for grammar engineering. Please help contribute or improve any questions and/or answers. Please prefix page names for answers with 'GeFaq'. See also the Grammar Engineering Glossary.

Getting started

• I want to install the LKB on my local machine, what should I do?

• What should I know about documenting my grammar?

• How do I interact with the LKB through the Lisp prompt?

Questions about error messages

• I don't think I'm getting any error messages. Does that mean I don't have any errors?

• The LKB says I have an error at position number 873. How do I figure out where that is in my file?

• When I try to load my grammar/the matrix, the LKB says "Error: Attempt to take the value of the unbound variable ...". What am I doing wrong?

• The LKB says I'm missing a right bracket, but I can't figure out where. What should I do?

• When I load my grammar, I get "no possible type for features (...) at path (...)". What is causing this?

• When I load my grammar, I get "Feature ... is introduced at multiple types (...)". What is causing this?

• My grammar loads just fine, but when I try to parse a sentence, it says "no sign can be constructed for ...". What's happening?

• It seems that errors in the lexicon are only detected when I try to parse a sentence containing a word with the error, not when the grammar is loaded. How do I check the whole lexicon?

• When I try to parse a sentence, the LKB says "probable runaway rule". How do I debug this?

• When I try to generate, the LKB says "probable runaway rule". How do I debug this?

• When I try to generate, the LKB says "Probable circular lexical rule". How do I debug this?

• The LKB says "Cyclic check found cycle at ...". What does this mean and how do I debug it?

• I'm trying to write a lexical (or phrase structure rule), but I get the error "Rule without daughter". What does this mean, and how should I fix it?

• The LKB says that I am trying to unify a NULL with CONS. What could the problem be?

• The LKB says that the Unification of rule-x and rule-y failed at path <>. What's that about?

• Unifications failed to reunify when drawing parse tree. What does this mean?

Questions about the parse chart

• How do I get the LKB to show me the parse chart?

• When I look at the parse chart, I don't see an edge that I'm expecting to be there. How do I find out why it's missing?

• How can I tell if an edge is missing in the parse chart?

• Looking at the parse chart, it seems that I do have an edge that spans the whole chart (accounts for all the words), but the LKB still says no parses found. What might be going on?

• How do I tell if I have an edge that spans the whole chart?

• One of my words is showing up in the chart twice. Why?

• One of my words branches to two lexical edges that look exactly the same. Why?

• One of my words isn't showing up in the chart at all. Why?

• I've tried to use interactive unification to find out why an edge can't be built, and it can be built interactively, but it's still not in the chart. What's going on?

• I get two (or more) parses for a sentence. How can I tell where the extra parse is coming from?

• I get two (or more) parses for a sentence, but the Compare window doesn't show any discriminators. Why not? (Same lexical rules applied in other order.)

Questions about lexical rules

• How do I get my lexical rules to apply in a particular order?

• I've written a lexeme-to-lexeme rule, how do I know what information I need to copy up?

• How do I know if my lexical rule should be lexeme-to-lexeme or lexeme-to-word?

• Is there such a thing as a word-to-word rule?

• I'm trying to write a lexical rule, but I get the error "Rule without daughters". What does this mean, and how should I fix it?

• I have written my lexical rule in the grammar file, but it still isn't getting applied. What could be preventing it from being used?

• I have a lexical rule that seems to be applying even when its phonological conditions aren't met. What's going on?

Questions about semantics

• Some of my relations/qeqs aren't showing up in the MRS for the whole parse. Why not?

• Someone told me that types x and y were semantically incompatible, but they do unify. Can they still be semantically incompatible?

• What is a filter rule, and how do I write one?

Questions about types, constraints, and entries

• What do the punctuation marks mean in the tdl files? (A very basic guide to tdl syntax.)

• How do I constrain something to be not of a certain value?

• How do I do disjunction (constrain the value of a feature to be X or Y)?

• Can I make the value of one feature dependent on the value of another?

• How do I define multiple different root conditions?

• How do I see what a type looks like with all of the constraints it inherits from supertypes?

• How do I look at fully specified lexical entries or rules?

• How do I see what definition the LKB has read in for a type?

• How do I browse the type hierarchy?

• How do I write a lexical entry for a word with spaces in it?

• What is a type addendum statement, and when should I use one?

• I've added a rule to my grammar but the LKB doesn't seem to have found it. What's happening?

• I'm trying to add a brand-new constraint on my subtypes, but it says that there is no unification path. What's wrong?

• I'm trying to combine constraints on my lexical items and it's saying it can't unify. What can I do?

Questions about features

• What is the feature geometry assigned in the Matrix? (Or: How do I figure out what paths I need to use?)

• I'm trying to add a new feature, and the LKB doesn't like it. What should I do?

• How do I get the LKB to tell me what type(s) a feature or set of features is appropriate for?

Other questions

• How do I do interactive unification?

• What should I know about downloading matrix patches?

• The LKB seems to be "forgetting" a constraint/definition I've coded. Why?

• In which files does order matter?

• A menu item seems to have disappeared (e.g., Parse > Compare or Generate). How do I get it back?

• How do I use tab to help me figure out where my syntax error is?

• I have a type/lexical entry/rule which doesn't seem to be inheriting a constraint from its supertype. What might be going on?

• I've downloaded an updated version of the matrix, but the changes specified in the new matrix.tdl don't seem to be taking effect when I reload the grammar. What's wrong?

• How do I change the default sentence that appears in the parse dialog box when I load up my grammar?

• What's a difference list, and why do we use them?

• All of the sudden, some of the nodes in my tree are labeled with ? instead of N or S or VP. What happened?

• How can I input strings from non-ascii character sets?

• What non-alphanumeric characters are allowed to be part of a string parsed by the LKB, and how can I change that?

• When I switch between grammars (e.g., the English Resource Grammar and a Matrix-derived grammar) the LKB sometimes behaves funny (errors, seg faults, etc.). What's going on?

• When I close the LKB Top Menu, is Lisp supposed to exit as well?

• How can I tell tsdb++ to start with the directories for "home" and "skeletons" that I want each time?

• Why doesn't my language appear in tsdb++ in the treehouse?

• In LKB, when I click on nodes in a parse chart, I don't get a pop-up menu. Why not?

• The keyboard doesn't work in the incr tsdb() window/The keyboard doesn't work in Emacs after running incr tsdb()

• How do I paste into the LKB Parse dialogue?