Address @dcreager's changes.

Author: Patrick Thomson

docs/adding-new-languages.md

@@ -2,15 +2,17 @@
 
 This document exists to outline the process associated with adding a new language to Semantic. Though the Semantic authors have architected the library such that adding new languages and syntax [requires no changes to existing code](https://en.wikipedia.org/wiki/Expression_problem), adding support for a new language is a nontrivial amount of work. Those willing to take the plunge will probably need a degree of Haskell experience.
 
+Please note that this list of steps reflects the state of Semantic as is, not where we authors are taking it: we're working on significant simplifications to this process (see the FAQs below).
+
 ## The procedure
 
 1. **Find or write a [tree-sitter](https://tree-sitter.github.io) parser for your language.** The tree-sitter [organization page](https://github.com/tree-sitter) has a number of parsers beyond those we currently support in Semantic; look there first to make sure you're not duplicating work. The tree-sitter [documentation on creating parsers](http://tree-sitter.github.io/tree-sitter/creating-parsers) provides an exhaustive look at the process of developing and debugging tree-sitter parsers. Though we do not support grammars written with other toolkits such as [ANTLR](https://www.antlr.org), translating an ANTLR or other BNF-style grammar into a tree-sitter grammar is usually straightforward.
 2. **Create a Haskell library providing an interface to that C source.** The [`haskell-tree-sitter`](https://github.com/tree-sitter/haskell-tree-sitter/tree/master/languages) repository provides a Cabal package for each supported language. You can find an example of a pull request to add such a package here. Each package needs to provide two API surfaces:
    * a bridged (via the FFI) reference to the toplevel parser in the generated file ([example](https://github.com/tree-sitter/haskell-tree-sitter/blob/master/languages/json/internal/TreeSitter/JSON/Internal.hs))
    * symbol datatypes for each syntax node in the parser, generated with the `mkSymbolDatatype` Template Haskell splice ([example](https://github.com/tree-sitter/haskell-tree-sitter/blob/master/languages/json/TreeSitter/JSON.hs))
-3. **Identify the new syntax nodes required to represent your language.** While we provide an extensive library of reusable AST nodes for [literals](https://github.com/github/semantic/blob/master/src/Data/Syntax/Literal.hs), [expressions](https://github.com/github/semantic/blob/master/src/Data/Syntax/Expression.hs), [statements](https://github.com/github/semantic/blob/master/src/Data/Syntax/Statement.hs), and [types](https://github.com/github/semantic/blob/master/src/Data/Syntax/Type.hs), most languages will require some syntax nodes not found in other languages. You'll need to create a new module providing those data types, and those data types must be written as an open union.
+3. **Identify the new syntax nodes required to represent your language.** While we provide an extensive library of reusable AST nodes for [literals](https://github.com/github/semantic/blob/master/src/Data/Syntax/Literal.hs), [expressions](https://github.com/github/semantic/blob/master/src/Data/Syntax/Expression.hs), [statements](https://github.com/github/semantic/blob/master/src/Data/Syntax/Statement.hs), and [types](https://github.com/github/semantic/blob/master/src/Data/Syntax/Type.hs), most languages will require some syntax nodes not found in other languages. You'll need to create a new module providing those data types, and those data types must be written as an open union: [here](https://github.com/github/semantic/commits/master/src/Language/Ruby/Syntax.hs?author=charliesome) is an example for Ruby's syntactic details.
 4. **Write an assignment step that translates tree-sitter trees into Haskell datatypes.** More information about this can be found in the [assignment documentation](assignment.md). This is currently the most time-consuming and error-prone part of the process (see [https://github.com/github/semantic/issues/77]).
-5. **Implement `Evaluatable` instances and add new [`Value` effects](https://github.com/github/semantic/blob/master/src/Control/Abstract/Value.hs) as is needed to describe the control flow of your language.** While several features of Semantic (e.g. symbol generation and diffing) work without requiring concrete or abstract interpretation, more advanced analyses require implementing the `Evaluatable` typeclass and providing value-style effects for each control flow feature provided by the language. This means that language support is a spectrum: Semantic can provide useful information without any knowledge of a language's semantics, but each successive addition to its interpretive capabilities enables more functionality.
+5. **Implement `Evaluatable` instances and add new [`Value` effects](https://github.com/github/semantic/blob/master/src/Control/Abstract/Value.hs) as is needed to describe the control flow of your language.** While several features of Semantic (e.g. `semantic parse --symbols` and `semantic diff`) will become fully available given a working assignment step, further features based on concrete or abstract interpretation (such as `semantic graph`) require implementing the `Evaluatable` typeclass and providing value-style effects for each control flow feature provided by the language. This means that language support is a spectrum: Semantic can provide useful information without any knowledge of a language's semantics, but each successive addition to its interpretive capabilities enables more functionality.
 6. **Add tests for diffing, tagging, graphing, and evaluating code written in that language.** Because tree-sitter grammars often change, we require extensive testing so as to avoid the unhappy situation of bitrotted languages that break as soon as a new grammar comes down the line.
 
 # FAQs