Fix up references to r.bqn

1 files changed, 24 insertions, 7 deletions

diff --git a/src/README.txt b/src/README.txt
index 2881a572..5b2f659b 100644
--- a/src/README.txt
+++ b/src/README.txt
@@ -1,15 +1,32 @@
 Documentation for BQN's implementation is at ../implementation/.
 
-BQN sources for BQN. Object code obtained from these sources is run with
-a VM to obtain a BQN implementation. This is done in Javascript in
-../docs/bqn.js and ../docs/repl.js.
+BQN sources for BQN. Object code from these is run with a VM to obtain a
+BQN implementation. The Javascript VM is ../docs/bqn.js.
+
+Compiler toolchain:
+
+- glyphs.bqn  Glyphs for all BQN primitives
+- c.bqn       Compiler
+- pp.bqn      General preprocessing
+- pr.bqn      Preprocess the runtime
+- cjs.bqn     Format compiler output as Javascript literals
+
+Compilation targets:
 
 - c.bqn  Compiler
-- r.bqn  Runtime
+- r0.bqn, r1.bqn  Runtime
 - f.bqn  Formatter
 - e.bqn  Expression syntax explainer
+- p.bqn  Plot generator
+
+Since it defines primitives, the runtime is only sort of BQN. This is
+why pr.bqn is required to process it. It's also compiled with a custom
+primitive set.
 
-Helper code used to obtain Javascript-formatted object code:
+e.bqn and p.bqn also require the definitions from svg.bqn; they are
+attached cjs.bqn.
 
-- pr.bqn   Preprocess the runtime
-- cjs.bqn  Format compiler output as Javascript literals
+Some of these files are also used elsewhere: pp.bqn preprocesses other
+primitive-defining code in ../test/ref.bqn and ../dzref, and f.bqn is
+used to format results in markdown while e.bqn generates diagrams for
+the tutorials.