new resource doc on Phrase etc

lib/resource-1.0/abstract/Sentence.gf

@@ -1,19 +1,53 @@
+--1 Clauses, imperatives, and sentential complements
+
 abstract Sentence = Cat ** {
 
+--2 Clauses
+
+-- The $NP VP$ predication rule form a clause whose linearization
+-- gives a table of all tense variants, positive and negative.
+-- Clauses are converted to $S$ (with fixed tense) in [Tensed Tensed.html].
+
   fun
+    PredVP    : NP -> VP -> Cl ;         -- John walks
 
-    PredVP   : NP -> VP -> Cl ;
-    PredSCVP : SC -> VP -> Cl ;
+-- Using an embedded sentence as a subject is treated separately.
+-- This can be overgenerating. E.g. "whether you go" as subject
+-- is only meaningful for some verb phrases.
 
-    ImpVP    : VP -> Imp ;
+    PredSCVP  : SC -> VP -> Cl ;         -- that you go makes me happy
 
-    SlashV2   : NP -> V2 -> Slash ;
-    SlashVVV2 : NP -> VV -> V2 -> Slash ;
-    AdvSlash  : Slash -> Adv -> Slash ;
-    SlashPrep : Cl -> Prep -> Slash ;
+--2 Clauses missing object noun phrases
+
+-- This category is a variant of the 'slash category' $S/NP$ of
+-- GPSG and categorial grammars, which in turn replaces
+-- movement transformations in the formation of questions
+-- and relative clauses. Except $SlashV2$, the construction 
+-- rules can be seen as special cases of function composition, in
+-- the style of CCG.
+-- *Note* the set is not complete and lacks e.g. verbs with more than 2 places.
+
+    SlashV2   : NP -> V2 -> Slash ;      -- (whom) he sees
+    SlashVVV2 : NP -> VV -> V2 -> Slash; -- (whom) he wants to see 
+    AdvSlash  : Slash -> Adv -> Slash ;  -- (whom) he sees tomorrow
+    SlashPrep : Cl -> Prep -> Slash ;    -- (with whom) he walks 
+
+--2 Imperatives
+
+-- An imperative is straightforwardly formed from a verb phrase.
+-- It has variation over positive and negative, singular and plural.
+-- To fix these parameters, see [Phrase Phrase.html].
+
+    ImpVP     : VP -> Imp ;              -- go
+
+--2 Embedded sentences
+
+-- Sentences, questions, and infinitival phrases can be used as
+-- subjects and (adverbial) complements.
+
+    EmbedS    : S  -> SC ;               -- that you go
+    EmbedQS   : QS -> SC ;               -- whether you go
+    EmbedVP   : VP -> SC ;               -- to go
 
-    EmbedS  : S  -> SC ;
-    EmbedQS : QS -> SC ;
-    EmbedVP : VP -> SC ;
 
 }