* src/ltlast/atomic_prop.hh, src/ltlast/binop.hh,

src/ltlast/constant.hh, src/ltlast/formula.hh,
src/ltlast/multop.hh, src/ltlast/refformula.hh,
src/ltlast/unop.hh, src/ltlast/visitor.hh, src/ltlenv/declenv.hh,
src/ltlenv/defaultenv.hh, src/ltlenv/environment.hh,
src/ltlparse/public.hh, src/ltlvisit/apcollect.hh,
src/ltlvisit/basicreduce.hh, src/ltlvisit/clone.hh,
src/ltlvisit/destroy.hh, src/ltlvisit/dotty.hh,
src/ltlvisit/dump.hh, src/ltlvisit/length.hh,
src/ltlvisit/lunabbrev.hh, src/ltlvisit/nenoform.hh: Add Doxygen
groups for LTL algorithms and types.
* doc/Makefile.am (fast-doc): New target.

src/ltlast/atomic_prop.hh

@@ -35,7 +35,8 @@ namespace spot
   namespace ltl
   {
 
-    /// Atomic propositions.
+    /// \brief Atomic propositions.
+    /// \ingroup ltl_ast
     class atomic_prop : public ref_formula
     {
     public:

src/ltlast/binop.hh

@@ -35,7 +35,8 @@ namespace spot
   namespace ltl
   {
 
-    /// Binary operator.
+    /// \brief Binary operator.
+    /// \ingroup ltl_ast
     class binop : public ref_formula
     {
     public:

src/ltlast/constant.hh

@@ -31,7 +31,8 @@ namespace spot
   namespace ltl
   {
 
-    /// A constant (True or False)
+    /// \brief A constant (True or False)
+    /// \ingroup ltl_ast
     class constant : public formula
     {
     public:

src/ltlast/formula.hh

@@ -30,8 +30,39 @@ namespace spot
 {
   namespace ltl
   {
+    /// \defgroup ltl LTL formulae
+    ///
+    /// This module gathers types and definitions related to LTL formulae.
+
+    /// \addtogroup ltl_essential Essential LTL types
+    /// \ingroup ltl
+
+    /// \addtogroup ltl_ast LTL Abstract Syntax Tree
+    /// \ingroup ltl
+
+    /// \addtogroup ltl_environment LTL environments
+    /// \ingroup ltl
+    /// LTL environment implementations.
+
+    /// \addtogroup ltl_algorithm Algorithms for LTL formulae
+    /// \ingroup ltl
+
+    /// \addtogroup ltl_io Input/Output of LTL formulae
+    /// \ingroup ltl_algorithm
+
+    /// \addtogroup ltl_visitor Derivable visitors
+    /// \ingroup ltl_algorithm
+
+    /// \addtogroup ltl_rewriting Rewriting LTL formulae
+    /// \ingroup ltl_algorithm
+
+    /// \addtogroup ltl_misc Miscellaneous algorithms for LTL formulae
+    /// \ingroup ltl_algorithm
+
 
     /// \brief An LTL formula.
+    /// \ingroup ltl_essential
+    /// \ingroup ltl_ast
     ///
     /// The only way you can work with a formula is to
     /// build a spot::ltl::visitor or spot::ltl::const_visitor.

src/ltlast/multop.hh

@@ -34,6 +34,7 @@ namespace spot
   {
 
     /// \brief Multi-operand operators.
+    /// \ingroup ltl_ast
     ///
     /// These operators are considered commutative and associative.
     class multop : public ref_formula

src/ltlast/refformula.hh

@@ -32,6 +32,7 @@ namespace spot
   {
 
     /// \brief A reference-counted LTL formula.
+    /// \ingroup ltl_ast
     class ref_formula : public formula
     {
     protected:

src/ltlast/unop.hh

@@ -32,7 +32,8 @@ namespace spot
   namespace ltl
   {
 
-    /// Unary operator.
+    /// \brief Unary operators.
+    /// \ingroup ltl_ast
     class unop : public ref_formula
     {
     public:

src/ltlast/visitor.hh

@@ -31,6 +31,7 @@ namespace spot
   namespace ltl
   {
     /// \brief Formula visitor that can modify the formula.
+    /// \ingroup ltl_essential
     ///
     /// Writing visitors is the prefered way
     /// to traverse a formula, since it doesn't