Rework leaf_data
The previous implementation of leaf_data used a grammar, where all of
the leaf_data_* parsers were tried one after another and then in each of
their on_success handlers, the type of leaf was checked against the
attribute of the parser. This leads to two problems:
1) Ambiguity. Example: 1 can be parsed as any of the integral parsers.
This can lead to a problems inside the parser (ambiguity is the reason
the parser doesn't work in newer Boost versions).
2) Order of the alternatives. Because the alternative parser can only be
defined at compile-time, there is no way to change the order of the
alternatives. Right now, this isn't a problem, since a leaf can only
have one type, but I'm going to need a way to reorder the parsers to
implement unions.
The new leaf_data parser is implemented by creating an entirely new type
of parser. A parser (as far as Spirit is concerned) is a class that
inherits from x3::parser and implements parse(), which returns whether
the parser passed or not. In this method I have access to ParserContext.
That means I can dynamically choose which parser is going to be used
according to the return value of Schema::leafType.
Another advantage is that now I don't need on_success handlers for basic
types and I can use the elemental parsers directly. Types like enum need
extra validation, so they keep their handlers. If I ever need extra
validation on more types, I can easily add some of the handlers back.
I also moved the createSetSuggestions handler to leaf_data.hpp since
it's directly connected to leaf_data (even the rule is defined in this
file).
Side note: the parser could have been implemented by using an
implementation of the lazy parser from here
https://github.com/boostorg/spirit/issues/530.
However, a Spirit developer suggested I just inherit from x3::parser and
use that.
Side note 2: all of the completion creators can be implemented in a
similar way, and that brings some advantages too.
Side note 3: the parser for paths can be rewritten in a similar way to
this, but right now it's not needed. When Boost gets updated, the
rewrite will happen then.
Change-Id: Ia29c1895833b811a45873f8490da9c64fa4742eb
diff --git a/CMakeLists.txt b/CMakeLists.txt
index d15c36a..eb6f15c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -125,6 +125,7 @@
src/interpreter.cpp
src/ast_handlers.cpp
src/completion.cpp
+ src/leaf_data.cpp
)
target_link_libraries(parser schemas utils ast_values)