Add EXTRA* variables

[Shushe] / README.markdown

diff --git a/README.markdown b/README.markdown
index 4427c7fed710eb40a5051e147688b77e1f843478..654904ae9eda3ab787fbdc83dc7b001778f5ffda 100644 (file)
--- a/README.markdown
+++ b/README.markdown
@@ -1,6 +1,6 @@
 # ⛩️📰 书社
 
-<b>An X·S·L·T‐based static site generator.</b>
+<b>A make·file for X·M·L.</b>
 
 <dfn>⛩️📰 书社</dfn> aims to make it easy to generate websites with
   X·S·L·T and G·N·U Make.
@@ -18,6 +18,15 @@ It makes things easier by :⁠—
 
 It aims to do this with zero dependencies beyond the programs already
   installed on your computer.
+(On Linux machines, you may need to install `libxml2-utils` to get the
+  commandline programs from `libxml2`.)
+
+**Note:**
+⛩️📰 书社 requires functionality present in G·N·U Make 3.81 (or later)
+  and will not work in previous versions, or other implementations of
+  Make.
+Compatibility with later versions of G·N·U Make is assumed, but not
+  tested.
 
 ## Nomenclature
 
@@ -98,6 +107,7 @@ In every case, you may supply your own implementation by overriding the
 - `echo`
 - `file`
 - `find`
+- `git` (optional; set `GIT=` to disable)
 - `mkdir` (requires support for `-p`)
 - `mv`
 - `od` (requires support for `-t x1`)
@@ -159,22 +169,39 @@ The following additional variables can be used to control the behaviour
 
 - **`FINDRULES`:**
   Rules to use with `find` when searching for source files.
-  The default ignores hidden files, those that start with a period or
-    hyphen‐minus, and those which contain a pipe, buck, percent, or
-    colon.
+  The default ignores files that start with a period or hyphen‐minus
+    and those which contain a hash, buck, percent, asterisk, colon,
+    semi, eroteme, bracket, backslash, or pipe.
+
+- **`EXTRAFINDRULES`:**
+  The value of this variable is appended to `FINDRULES` by default, to
+    enable additional rules without overriding the existing ones.
 
 - **`FINDINCLUDERULES`:**
   Rules to use with `find` when searching for includes (default:
     `$(FINDRULES)`).
 
+- **`EXTRAFINDINCLUDERULES`:**
+  The value of this variable is appended to `FINDINCLUDERULES` by
+    default, to enable additional rules without overriding the existing
+    ones.
+
 - **`PARSERS`:**
   A white·space‐separated list of parsers to use (default:
     `$(THISDIR)/parsers/*.xslt`).
 
+- **`EXTRAPARSERS`:**
+  The value of this variable is appended to `PARSERS` by default, to
+    enable additional parsers without overriding the existing ones.
+
 - **`TRANSFORMS`:**
   A white·space‐separated list of transforms to use (default:
     `$(THISDIR)/transforms/*.xslt`).
 
+- **`EXTRATRANSFORMS`:**
+  The value of this variable is appended to `TRANSFORMS` by default, to
+    enable additional transforms without overriding the existing ones.
+
 - **`XMLTYPES`:**
   A white·space‐separated list of media types to consider X·M·L
     (default: `application/xml text/xml`).
@@ -207,10 +234,11 @@ Text formats with associated X·S·L·T parsers are wrapped in a H·T·M·L
 Source files whose media type does not have an associated X·S·L·T
   parser are considered “assets” and will not be transformed.
 
-**☡ For compatibility with this program, source filenames must not
-  contain Ascii whitespace, colons (`:`), pipes (`|`), bucks (`$`),
-  percents (`%`) or control characters, and must not begin with a
-  hyphen‐minus (`-`).**
+**☡ For compatibility with this program, source file·names must not
+  contain Ascii white·space, colons (`:`), semis (`;`), pipes (`|`),
+  bucks (`$`), percents (`%`), hashes (`#`), asterisks (`*`), brackets
+  (`[` or `]`), erotemes (`?`), backslashes (`\`), or control
+  characters, and must not begin with a hyphen‐minus (`-`).**
 The former characters have the potential to conflict with make syntax,
   and a leading hyphen‐minus is confusable for a command‐line argument.
 
@@ -374,10 +402,32 @@ The following are recommendations on effective creation of
 - Set `@exclude-result-prefixes` on the root `xslt:transform` element
     to reduce the number of declared namespaces in the final result.
 
-The params `$buildtime`, `$srctime`, and `$path` are available within
-  transforms and are initialized to the current time, the time that the
-  source file was last modified, and the path of the output file within
-  $(DESTDIR).
+## Global Params
+
+The following params are made available globally in parsers and
+  transforms :⁠—
+
+- **`BUILDTIME`:**
+  The current time.
+
+- **`SRCREV`:**
+  The tag or hash of the current commit in the working directory (if
+    `GIT` is defined and `./.git` exists).
+
+- **`SRCTIME`:**
+  The time at which the source file was last modified.
+
+- **`VERSION`:**
+  The tag or hash of the current commit in `THISDIR` (if `GIT` is
+    defined and `$(THISDIR)/.git` exists).
+
+The following params are only available in transforms :⁠—
+
+- **`CATALOG`:**
+  The path of the catalog file (within `BUILDDIR`).
+
+- **`PATH`:**
+  The path of the output file (within `DESTDIR`).
 
 ## Output Wrapping
 
@@ -438,4 +488,4 @@ Source files are licensed under the terms of the <cite>Mozilla Public
   License, version 2.0</cite>.
 For more information, see [LICENSE](./LICENSE).
 
-[draft-phillips-record-jar-01]: <https://datatracker.ietf.org/doc/html/draft-phillips-record-jar-01>
\ No newline at end of file
+[draft-phillips-record-jar-01]: <https://datatracker.ietf.org/doc/html/draft-phillips-record-jar-01>