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Eev and Lean4

I am trying to learn Lean4. It's more fun than Agda. My messy notes about Lean are in lean.e.

Index:


1. LuaTreeLean

This is an attempt to port my LuaTree thing from Maxima to Lean. Its git repository is here. Click on the screenshot below to enlarge.


2. A problem with import

I am trying to learn how to split my programs into a "library" - let's suppose that it is called A.lean - and "tests", called, say, B.lean and C.lean. In theory I should just need a minimal Lakefile, like this one from LuaTreeLean, and a line like "import A" in the beginning of B.lean and C.lean, but apparently I am stumbling on bugs... in the test below - that is also here - the "import A" in B.lean works from "lake build" but not from "lean B.lean" or from Emacs:

 (eepitch-shell)
 (eepitch-kill)
 (eepitch-shell)
rm -Rfv /tmp/import-test/
mkdir   /tmp/import-test/
cd      /tmp/import-test/

cat > A.lean <<'%%%'
  def a := "42"
  #eval a
%%%
cat > B.lean <<'%%%'
  import A
  #eval a
  def main : IO Unit := IO.println s!"Hello {a}"
%%%
cat > lakefile.lean <<'%%%'
  import Lake
  open   Lake DSL
  package A
  @[default_target] lean_lib A
  @[default_target] lean_exe b { root := `B } 
%%%

 lake build            ;# ok
.lake/build/bin/b      ;# ok
lean A.lean            ;# ok
lean B.lean            ;# unknown package 'A'

find * .lake/ | sort

# (find-fline "/tmp/import-test/")
# (find-fline "/tmp/import-test/A.lean")
# (find-fline "/tmp/import-test/B.lean")

Click on the screenshot to enlarge. I asked a question about this in the Zulip Chat in this thread; TODO: explain why using /tmp/a.lean as a scratch file may be a bad idea, and how to fix LSP when it gets confused...!


3. Questions

Here are links to some of my questions on the Lean Zulip Chat:

  • (z,e) (2024jun16) Elaborators for other syntax categories?
  • (z,e) (2024jun15) "require from git" works in Emacs but not in the shell
  • (z,e) (2024jun15) Introducing Partax, the Parser Compiler
  • (z,e) (2024jun11) Is there a variant of repr that "prints the type"?
  • (z,e) (2024jun09) Need help to debug an import - and maybe a lakefile
  • (z,e) (2024jun09) Announcement: LuaTreeLean (not a question)
  • (z,e) (2024jun07) Minimal setup for importing .lean files in the same directory
  • (z,e) (2024jun03) run_cmd, monads, and tests for their methods
  • (z,e) (2024jun01) "failed to synthesize instance ToLuaTree Name" inside "instance : ToLuaTree Name"
  • (z,e) (2024may25) Tools for exploring data structures?
  • (z,e) (2024may20) How do I translate Agda's "postulate" to Lean?
  • (z,e) (2024may19) Where is this shorthand for match documented?
  • (z,e) (2024may18) A command that prints the current namespace?
  • (z,e) (2024may15) How do I write a "#check_syntax"?
  • (z,e) (2024may13) leading_parser?
  • (z,e) (2024apr28) Recommended ways to convert Lean4 code to LaTeX?
  • (z,e) (2024mar11) IO.Process.output with stdin being a string?
  • (z,e) (2023jun26) ~/.agda/defaults and ~/agda/libraries, but in Lean?


4. Adapting eev-rstdoc.el to Lean

(TODO: explain this!)

(find-lean4doc     "whatIsLean")
(find-fplean4doc   "getting-to-know/evaluating")
(find-leanmetadoc  "main/01_intro")
(find-leantpildoc  "introduction")
(find-leanmathsdoc "C02_Basics#calculating")
(find-leanrefdoc   "using_lean#using-lean-with-emacs")
(find-angg         ".emacs.lean.el")


5. Snippets

My notes on Lean are here: lean.e. They are indexed using anchors, are divided into e-script blocks, and most of these e-script blocks are made of a series of elisp hyperlinks - actually "shorter hyperlinks" - followed by a snippet, like this:

# (find-leanmetadoc  "main/02_overview")
# (find-leanmetadocr "main/02_overview.lean")
# (find-leanmetapage  9 "3 essential commands and their syntax sugars")
# (find-leanmetatext  9 "3 essential commands and their syntax sugars")
# (find-leanmetapage 11 "This image is not supposed")
# (find-leanmetatext 11 "This image is not supposed")
# (ee-copy-rest-3 nil "-- end" "/tmp/a.lean")

import Lean
open Lean Elab Command

elab "#withstring " x:str : command =>
  match x with
  | `("a") => logInfo x
  | `("b") => do { logInfo x; logInfo (repr x) }
  | `("c") => do { logInfo x; logInfo (repr x.raw) }
  | _ => Elab.throwUnsupportedSyntax

#withstring "a"
#withstring "b"
#withstring "c"

-- end

My htmlizer only htmlizes a few of these links. The links that end in "doc" and "docr" are implemented in elisp using eev-rstdoc.el - see this presentation - and the (undocumented) code in .emacs.lean.el; the links that end in "text" are explained here.