Add some explanatory comments

1 files changed, 13 insertions, 0 deletions

diff --git a/dhall_parser/src/lib.rs b/dhall_parser/src/lib.rs
index 94b49b5..e0843af 100644
--- a/dhall_parser/src/lib.rs
+++ b/dhall_parser/src/lib.rs
@@ -1 +1,14 @@
+// This crate only contains the grammar-generated parser. The rest of the
+// parser is in dhall_core. This separation is because compiling the
+// grammar-generated parser is extremely slow. Eventually, the whole parser
+// should probably be moved to here.
+// See the https://pest.rs documentation for details on what this crate contains.
+// The pest file is auto-generated and is located at ./dhall.pest.
+// It is generated from grammar.abnf in a rather straightforward manner. Some
+// additional overrides are done in ../build.rs.
+// The lines that are commented out in ./dhall.pest.visibility are marked as
+// silent (see pest docs for what that means) in the generated pest file.
+// The abnf file has quite a lot of modifications compared to the one from
+// the standard. Hopefully those changes should be merged upstream, but for now
+// feel free to edit it to make parsing easier.
 include!(concat!(env!("OUT_DIR"), "/grammar.rs"));