v0.3.0

Changed

• Require Nim v1.4.0.

• The returned tuple for the find_declaration() procedure now includes any
  expression node if the declaration involves an assignment. Otherwise, this
  field is set to nil.

• Ranged expressions with : is now an infix node.

• Refactored the module graph type (graph.nim) and its interface.

  Parsing a Verilog source file now involves attempting to look up the
  declarations of all modules instantiated within.

• Refactored the iterators walk_ports() and walk_parameters() to simplify
  logic in user applications.

Added

• Add module caching. The user has to manage the module cache and location
  database and initialize each new module graph with these objects. See
  graph.nim:new_graph().
• Add interface find_all_drivers() to simplify extracting driver nodes from
  the AST.
• Add interface find_all_ports() and find_all_parameters().
• Add a set for the node types involved in expressions.
• Add the option to specify the start of the search for the various
  find_first() functions.
• Add operators [] and []= to AST nodes. This is shorthand to access the
  sequence of sons for nonprimitive nodes, i.e. n[i] is equivalent to
  n.sons[i].
• Define the len() proc for nonprimitive AST nodes. The operation is
  equivalent to len(n.sons).
• For completeness, performing a declaration lookup with a module instance name
  leads back to the instantiation itself.
• Add is_external_identifier() to the AST API.
• Add find_external_identifier(), find_module_port_declaration() and
  find_module_parameter_declaration() to the module graph API.
• Add the iterator walk_port_references().
• Module declaration nodes now include the leading comment token.
• An include path ending with '**' implies a recursive include.

Fixed

• Disable colored output when stdout does not lead to a terminal.

• Fix find_all_parameters() always including the parameters declared in the
  module body. Like ports, these only get included if the parameter port list is
  omitted.

• Fix an issue where the lexer would throw an exception when parsing a decimal
  constant larger than 64 bits.

• Hierarchical identifiers like foo.bar[1].baz[3:0] are now supported.
  Previously, only ranged identifiers was allowed and the scoping syntax with
  . didn't work.

• Fix an issue where operators were not being lexed correctly.

  The issue occurred when a an infix operator was immediately followed by a
  prefix operator, i.e. not separated by whitespace. Before this fix an
  expression like a|~b would be lexed as a, |~ and b instead of a,
  |, ~ and b like it should.

• Fix find_declaration() not yielding the declaration when the target
  identifier is a port reference.

Removed

• Remove AST nodes NkVariableLvalue and NkArrayIdentifier.
• Remove special identifier node types like NkPortIdentifier and
  NkModuleIdentifier in favor of the generic NkIdentifier.
• Remove NkParameterAssignment, use NkAssignment instead.