doc/lisp: add links to sections and upstream websites

Also clean up complex paragraphs and fix section on building wrappers

1 files changed, 29 insertions, 51 deletions

diff --git a/doc/languages-frameworks/lisp.section.md b/doc/languages-frameworks/lisp.section.md
index 94d99b0392ad4..53ddee837602c 100644
--- a/doc/languages-frameworks/lisp.section.md
+++ b/doc/languages-frameworks/lisp.section.md
@@ -1,36 +1,32 @@
 # lisp-modules {#lisp}
 
 This document describes the Nixpkgs infrastructure for building Common Lisp
-libraries that use ASDF (Another System Definition Facility). It lives in
-`pkgs/development/lisp-modules`.
+systems that use [ASDF](https://asdf.common-lisp.dev/) (Another System
+Definition Facility). It lives in `pkgs/development/lisp-modules`.
 
 ## Overview {#lisp-overview}
 
 The main entry point of the API are the Common Lisp implementation packages
-themselves (e.g. `abcl`, `ccl`, `clasp-common-lisp`, `clisp` `ecl`,
+themselves (e.g. `abcl`, `ccl`, `clasp-common-lisp`, `clisp`, `ecl`,
 `sbcl`). They have the `pkgs` and `withPackages` attributes, which can be used
 to discover available packages and to build wrappers, respectively.
 
-The `pkgs` attribute set contains packages that were automatically imported from
-Quicklisp, and any other manually defined ones. Not every package works for all
-the CL implementations (e.g. `nyxt` only makes sense for `sbcl`).
+The `pkgs` attribute set contains packages that were automatically
+[imported](#lisp-importing-packages-from-quicklisp) from Quicklisp, and any
+other [manually defined](#lisp-defining-packages-inside) ones. Not every package
+works for all the CL implementations (e.g. `nyxt` only makes sense for `sbcl`).
 
-The `withPackages` function is of primary utility. It is used to build runnable
-wrappers, with a pinned and pre-built ASDF FASL available in the `ASDF`
-environment variable, and `CL_SOURCE_REGISTRY`/`ASDF_OUTPUT_TRANSLATIONS`
-configured to find the desired systems on runtime.
-
-With a few exceptions, the primary thing that the infrastructure does is to run
-`asdf:load-system` for each system specified in the `systems` argument to
-`build-asdf-system`, and save the FASLs to the Nix store. Then, it makes these
-FASLs available to wrappers. Any other use-cases, such as producing SBCL
-executables with `sb-ext:save-lisp-and-die`, are achieved via overriding the
-`buildPhase` etc.
+The `withPackages` function is of primary utility. It is used to build 
+[runnable wrappers](#lisp-building-wrappers), with a pinned and pre-built 
+[ASDF FASL](#lisp-loading-asdf) available in the `ASDF` environment variable, 
+and `CL_SOURCE_REGISTRY`/`ASDF_OUTPUT_TRANSLATIONS` configured to 
+[find the desired systems on runtime](#lisp-loading-systems).
 
 In addition, Lisps have the `withOverrides` function, which can be used to
-substitute any package in the scope of their `pkgs`. This will be useful
-together with `overrideLispAttrs` when dealing with slashy ASDF systems, because
-they should stay in the main package and be built by specifying the `systems`
+[substitute](#lisp-including-external-pkg-in-scope) any package in the scope of
+their `pkgs`. This will also be useful together with `overrideLispAttrs` when
+[dealing with slashy systems](#lisp-dealing-with-slashy-systems), because they
+should stay in the main package and be built by specifying the `systems`
 argument to `build-asdf-system`.
 
 ## The 90% use case example {#lisp-use-case-example}
@@ -94,7 +90,7 @@ The maintainer's job is to:
 
 1. Re-run the `ql-import.lisp` script when there is a new Quicklisp release
 2. [Add any missing native dependencies](#lisp-quicklisp-adding-native-dependencies) in `ql.nix`
-3. For packages that still don't build, package them manually in `packages.nix`
+3. For packages that still don't build, [package them manually](#lisp-defining-packages-inside) in `packages.nix`
 
 Also, the `imported.nix` file **must not be edited manually**! It should only be
 generated as described in this section (by running `ql-import.lisp`).
@@ -139,13 +135,14 @@ During Quicklisp import:
 
 ## Defining packages manually inside Nixpkgs {#lisp-defining-packages-inside}
 
-New packages, that for some reason are not in Quicklisp, and so cannot be
-auto-imported, can be written in the `packages.nix` file.
+Packages that for some reason are not in Quicklisp, and so cannot be
+auto-imported, or don't work straight from the import, are defined in the
+`packages.nix` file.
 
 In that file, use the `build-asdf-system` function, which is a wrapper around
 `mkDerivation` for building ASDF systems. Various other hacks are present, such
 as `build-with-compile-into-pwd` for systems which create files during
-compilation.
+compilation (such as cl-unicode).
 
 The `build-asdf-system` function is documented with comments in
 `nix-cl.nix`. Also, `packages.nix` is full of examples of how to use it.
@@ -203,28 +200,6 @@ sbcl.pkgs.alexandria.overrideLispAttrs (oldAttrs: rec {
 })
 ```
 
-## Overriding packages in scope {#lisp-overriding-packages-in-scope}
-
-Packages can be woven into a new scope by using `withOverrides`:
-
-```
-let
-  sbcl' = sbcl.withOverrides (self: super: {
-    alexandria = super.alexandria.overrideLispAttrs (oldAttrs: rec {
-      pname = "alexandria";
-      version = "1.4";
-      src = fetchFromGitLab {
-        domain = "gitlab.common-lisp.net";
-        owner = "alexandria";
-        repo = "alexandria";
-        rev = "v${version}";
-        hash = "sha256-1Hzxt65dZvgOFIljjjlSGgKYkj+YBLwJCACi5DZsKmQ=";
-      };
-    });
-  });
-in builtins.elemAt sbcl'.pkgs.bordeaux-threads.lispLibs 0
-```
-
 ### Dealing with slashy systems {#lisp-dealing-with-slashy-systems}
 
 Slashy (secondary) systems should not exist in their own packages! Instead, they
@@ -245,8 +220,8 @@ ecl.pkgs.alexandria.overrideLispAttrs (oldAttrs: {
 })
 ```
 
-See the respective section on using `withOverrides` for how to weave it back
-into `ecl.pkgs`.
+See the [respective section](#lisp-including-external-pkg-in-scope) on using
+`withOverrides` for how to weave it back into `ecl.pkgs`.
 
 Note that sometimes the slashy systems might not only have more dependencies
 than the main one, but create a circular dependency between `.asd`
@@ -258,13 +233,16 @@ Wrappers can be built using the `withPackages` function of Common Lisp
 implementations (`abcl`, `ecl`, `sbcl` etc.):
 
 ```
-sbcl.withPackages (ps: [ ps.alexandria ps.bordeaux-threads ])
+nix-shell -p 'sbcl.withPackages (ps: [ ps.alexandria ps.bordeaux-threads ])'
 ```
 
-Such a wrapper can then be executed like this:
+Such a wrapper can then be used like this:
 
 ```
-result/bin/sbcl
+$ sbcl
+* (load (sb-ext:posix-getenv "ASDF"))
+* (asdf:load-system 'alexandria)
+* (asdf:load-system 'bordeaux-threads)
 ```
 
 ### Loading ASDF {#lisp-loading-asdf}