X-Git-Url: https://git.ladys.computer/Shushe/blobdiff_plain/751a861d9f521d4c8472bb754e7438e675aaf8a5..61599492d0451c48f963a13a78a11a59415eb6f0:/README.markdown?ds=sidebyside

diff --git a/README.markdown b/README.markdown
index 8a0ebe1..3375b8a 100644
--- a/README.markdown
+++ b/README.markdown
@@ -21,16 +21,12 @@ It makes things easier by :⁠—
 - Enabling easy inclusion of source files within each other.
 
 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`.)
+  installed on your computer†.
 
-**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.
+† Assuming an operating system with a fairly featureful, and
+  Posix‐compliant, development setup (e·g, macOS).
+In fact, on Linux you will probably need to install a few programs:
+  `libxml2-utils`, `xsltproc`, `sharutils`, and `pax`.
 
 ## Nomenclature
 
@@ -52,6 +48,77 @@ The name <i lang="cmn-Hans">书社</i> was chosen to play on this pun, as
 In Ascii environments, ⛩️📰 书社 should be written `Shushe`, following
   the pinyin transliteration.
 
+## Prerequisites
+
+In most cases, ⛩️📰 书社 aims to require only functionality which is
+  present in all Posix‐compliant operating systems.
+There are a few exceptions.
+Details on particular programs are given below; if a program is not
+  listed, it is assumed that any Posix‐compliant implementation will
+  work.
+
+### `file`
+
+This is a Posix utility, but ⛩️📰 书社 currently depends on
+  unspecified behaviour.
+It requires support for the following additional options :⁠—
+
+- **`-C`**, when supplied with `-m`, must be useable to compile a
+    `.mgc` magicfile for use with future invocations of `file`.
+
+- **`--files-from`** must be useable to provide a file that `file`
+    should read file·names from, and `-` must be useable in this
+    context to specify the standard input.
+
+- **`--mime-type`** must cause `file` to print the internet media type
+    of the file with no charset parameter.
+
+- **`--separator`** must be useable to set the separator that `file`
+    uses to separate file names from types.
+
+These options are implemented by the
+  [Fine Free File Command](https://darwinsys.com/file/), which is used
+  by most operating systems.
+
+### `git`
+
+This is not a Posix utility.
+Usage of `git` is optional, but recommended (and activated by default).
+To disable it, set `GIT=`.
+
+### `make`
+
+This is a Posix utility, but ⛩️📰 书社 currently depends on
+  unspecified behaviour.
+⛩️📰 书社 requires specifically the G·N·U version of `make`, and
+  depends on functionality present in version 3.81 or later.
+It is not expected to work in previous versions, or with other
+  implementations of Make.
+
+### `pax`
+
+This is a Posix utility, but not included in the Linux Standard Base or
+  installed by default in many distributions.
+Only `ustar` format support is required.
+
+### `uudecode` and `uuencode`
+
+These are Posix utilities, but not included in the Linux Standard Base
+  or installed by default in many distributions.
+The G·N·U [Sharutils](https://www.gnu.org/software/sharutils/) package
+  can be installed to access them.
+
+### `xmlcatalog` and `xmllint`
+
+These are not a Posix utilities.
+They is a part of `libxml2`, but may need to be installed separately
+  (e·g by the name `libxml2-utils`).
+
+### `xsltproc`
+
+This is not a Posix utility.
+It is a part of `libxslt`, but may need to be installed separately.
+
 ## Basic Usage
 
 Place source files in `sources/` and run `make install` to compile
@@ -117,26 +184,26 @@ In every case, you may supply your own implementation by overriding the
 - `cksum`
 - `cp`
 - `date`
-- `echo`
 - `file`
 - `find`
 - `git` (optional; set `GIT=` to disable)
+- `grep`
 - `ln`
-- `mkdir` (requires support for `-p`)
+- `ls`
+- `mkdir`
 - `mv`
-- `od` (requires support for `-t x1`)
+- `od`
 - `pax` (only when generating archives)
 - `printf`
 - `rm`
 - `sed`
 - `sleep`
-- `stat`
 - `test`
 - `touch`
-- `tr` (requires support for `-d`)
-- `uuencode` (requires support for `-m` and `-r`)
-- `uudecode` (requires support for `-m` and `-r`)
-- `xargs` (requires support for `-0`)
+- `tr`
+- `uuencode`
+- `uudecode`
+- `xargs`
 - `xmlcatalog` (provided by `libxml2`)
 - `xmllint` (provided by `libxml2`)
 - `xsltproc` (provided by `libxslt`)
@@ -225,8 +292,8 @@ The following additional variables can be used to control the behaviour
     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`).
+  A white·space‐separated list of media types or media type suffixes to
+    consider X·M·L (default: `application/xml text/xml +xml`).
 
 - **`THISREV`:**
   The current version of ⛩️📰 书社 (default: derived from the current
@@ -236,6 +303,15 @@ The following additional variables can be used to control the behaviour
   The current version of the source files (default: derived from the
     current git tag/branch/commit).
 
+- **`QUIET`:**
+  If this variable has a value, informative messages will not be
+    printed (default: empty).
+  Informative messages print to stderr, not stdout, so disabling them
+    usually shouldn’t be necessary.
+  This does not (cannot) disable messages from Make itself, for which
+    the `-s`, `--silent` ∕ `--quiet` Make option is more likely to be
+    useful.
+
 - **`VERBOSE`:**
   If this variable has a value, every recipe instruction will be
     printed when it runs (default: empty).
@@ -268,11 +344,11 @@ Source files whose media type does not have an associated X·S·L·T
   contain Ascii white·space, colons (`:`), semis (`;`), pipes (`|`),
   bucks (`$`), percents (`%`), hashes (`#`), asterisks (`*`), brackets
   (`[` or `]`), erotemes (`?`), backslashes (`\`), or control
-  characters, must not begin with a hyphen‐minus (`-`), and must not
-  end with a cloparen (`)`).**
+  characters, must not begin with a hyphen‐minus (`-`), and must not end
+  with a cloparen (`)`).**
 The former characters have the potential to conflict with make syntax,
-  a leading hyphen‐minus is confusable for a command‐line argument, and
-  a trailing cloparen [activates a bug in G·N·U Make
+  a leading hyphen‐minus is confusable for a commandline argument, and a
+  trailing cloparen [activates a bug in G·N·U Make
   3.81](https://stackoverflow.com/questions/17148468/capturing-filenames-including-parentheses-with-gnu-makes-wildcard-function#comment24825307_17148894).
 
 ## Parsers
@@ -495,6 +571,10 @@ The following params are made available globally in parsers and
 
 - **`SRCTIME`:**
   The time at which the source file was last modified.
+  Due to limitations in Posix, this time will only have minute
+    precision if the file was modified in the last six months, and will
+    only have day precision if the file is older.
+  Users should not expect this value to be particularly stable.
 
 - **`THISREV`:**
   The value of the `THISREV` variable (if present).
@@ -600,6 +680,13 @@ They are :⁠—
     non X·M·L output types, ⁊·c).
   Other child elements will be ignored.
 
+  If the `<书社:archive>` element is given an `@书社:expanded`
+    attribute, rather than producing a tarball ⛩️📰 书社 will output
+    the directory which expanding the tarball would produce.
+  This mechanism can be used to generate multiple files from a single
+    source, provided all of the files are contained with·in the same
+    directory.
+
 - **`<书社:base64-binary>`:**
   The text nodes in the transformation result will, after removing all
     Ascii whitespace, be treated as a Base·64 string, which is then