new launch argument: `--list-cols`

8 files changed, 128 insertions, 35 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 00323a6..b826ac4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+### next
+- `--list-cols` launch argument
+
 <a name="v2.1.0"></a>
 ### v2.1.0 - 2022/02/23
 - fix failure in parsing `--cols` arguments with underscore
diff --git a/Cargo.lock b/Cargo.lock
index f38aab6..696cd93 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -243,7 +243,7 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "lfs"
-version = "2.1.0"
+version = "2.1.1-dev"
 dependencies = [
  "argh",
  "crossterm",
diff --git a/Cargo.toml b/Cargo.toml
index bfdc3e4..199727a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "lfs"
-version = "2.1.0"
+version = "2.1.1-dev"
 authors = ["dystroy <denys.seguret@gmail.com>"]
 edition = "2021"
 keywords = ["linux", "filesystem", "fs"]
diff --git a/src/args.rs b/src/args.rs
index 98c28f3..8195815 100644
--- a/src/args.rs
+++ b/src/args.rs
@@ -3,6 +3,7 @@ use {
         cols::Cols,
         units::Units,
     },
+    crossterm::tty::IsTty,
     argh::FromArgs,
     std::path::PathBuf,
 };
@@ -24,6 +25,10 @@ pub struct Args {
     #[argh(switch, short = 'a')]
     pub all: bool,
 
+    /// list the available column names
+    #[argh(switch)]
+    pub list_cols: bool,
+
     /// columns, eg `-c +inodes` or `-c id+dev+default`
     #[argh(option, default = "Default::default()", short = 'c')]
     pub cols: Cols,
@@ -71,3 +76,9 @@ impl argh::FromArgValue for Units {
         }
     }
 }
+impl Args {
+    pub fn color(&self) -> bool {
+        self.color.value()
+            .unwrap_or_else(|| std::io::stdout().is_tty())
+    }
+}
diff --git a/src/col.rs b/src/col.rs
index c5a9ff6..9120920 100644
--- a/src/col.rs
+++ b/src/col.rs
@@ -7,7 +7,10 @@ use {
 };
 
 macro_rules! col_enum {
-    ($($variant:ident $name:literal $($alias:literal)* : $title:literal ,)*) => {
+    (@just_variant $variant:ident $discarded:ident) => {
+        Col::$variant
+    };
+    ($($variant:ident $name:literal $($alias:literal)* : $title:literal $($def:ident)*,)*) => {
         /// A column of the lfs table.
         #[derive(Debug, Clone, Copy, PartialEq)]
         pub enum Col {
@@ -16,6 +19,11 @@ macro_rules! col_enum {
         pub static ALL_COLS: &[Col] = &[
             $(Col::$variant,)*
         ];
+        pub static DEFAULT_COLS: &[Col] = &[
+            $(
+                $(col_enum!(@just_variant $variant $def),)*
+            )*
+        ];
         impl FromStr for Col {
             type Err = ParseColError;
             fn from_str(s: &str) -> Result<Self, ParseColError> {
@@ -54,44 +62,44 @@ macro_rules! col_enum {
                     )*
                 }
             }
+            pub fn aliases(self) -> &'static [&'static str] {
+                match self {
+                    $(
+                        Self::$variant => &[$($alias,)*],
+                    )*
+                }
+            }
+            pub fn is_default(self) -> bool {
+                DEFAULT_COLS.contains(&self)
+            }
         }
-    }
+    };
 }
 
 // definition of all columns and their names
 // in the --cols definition
 col_enum!(
-    // syntax: Variant name [alias] : title
+    // syntax:
+    // Variant name [aliases]: title [default]
     Id "id": "id",
-    Dev "dev": "dev",
-    Filesystem "fs" "filesystem": "filesystem",
+    Dev "dev" "device" "device_id": "dev",
+    Filesystem "fs" "filesystem": "filesystem" default,
     Label "label": "label",
-    Type "type": "type",
-    Disk "disk": "disk",
-    Used "used": "used",
-    Use "use": "use%",
+    Type "type": "type" default,
+    Disk "disk" "dsk": "disk" default,
+    Used "used": "used" default,
+    Use "use": "use%" default,
     UsePercent "use_percent": "use%",
-    Free "free": "free",
-    Size "size": "size",
-    InodesUsed "inodes_used": "used inodes",
-    InodesUse "inodes" "inodes_use": "inodes%",
-    InodesUsePercent "inodes_use_percent": "inodes%",
-    InodesFree "inodes_free": "free inodes",
-    InodesCount "inodes_total" "inodes_count": "inodes total",
-    MountPoint "mount" "mount_point": "mount point",
+    Free "free": "free" default,
+    Size "size": "size" default,
+    InodesUsed "inodes_used" "iused": "used inodes",
+    InodesUse "inodes" "ino" "inodes_use" "iuse": "inodes%",
+    InodesUsePercent "inodes_use_percent" "iuse_percent": "inodes%",
+    InodesFree "inodes_free" "ifree": "free inodes",
+    InodesCount "inodes_total" "inodes_count" "itotal": "inodes total",
+    MountPoint "mount" "mount_point" "mp": "mount point" default,
 );
 
-pub static DEFAULT_COLS: &[Col] = &[
-    Col::Filesystem,
-    Col::Type,
-    Col::Disk,
-    Col::Used,
-    Col::Use,
-    Col::Free,
-    Col::Size,
-    Col::MountPoint,
-];
-
 impl Col {
     pub fn header_align(self) -> Alignment {
         match self {
@@ -106,8 +114,8 @@ impl Col {
             Self::Dev => Alignment::Center,
             Self::Filesystem => Alignment::Left,
             Self::Label => Alignment::Left,
-            Self::Disk => Alignment::Center,
             Self::Type => Alignment::Center,
+            Self::Disk => Alignment::Center,
             Self::Used => Alignment::Right,
             Self::Use => Alignment::Right,
             Self::UsePercent => Alignment::Right,
@@ -121,6 +129,27 @@ impl Col {
             Self::MountPoint => Alignment::Left,
         }
     }
+    pub fn description(self) -> &'static str {
+        match self {
+            Self::Id => "mount point id",
+            Self::Dev => "device id",
+            Self::Filesystem => "filesystem",
+            Self::Label => "volume label",
+            Self::Type => "filesystem type",
+            Self::Disk => "storage type",
+            Self::Used => "size used",
+            Self::Use => "usage graphical view",
+            Self::UsePercent => "percentage of blocks used",
+            Self::Free => "free bytes",
+            Self::Size => "total size",
+            Self::InodesUsed => "number of inodes used",
+            Self::InodesUse => "graphical view of inodes usage",
+            Self::InodesUsePercent => "percentage of inodes used",
+            Self::InodesFree => "number of free inodes",
+            Self::InodesCount => "total count of inodes",
+            Self::MountPoint => "mount point",
+        }
+    }
 }
 
 
diff --git a/src/list_cols.rs b/src/list_cols.rs
new file mode 100644
index 0000000..542a6a4
--- /dev/null
+++ b/src/list_cols.rs
@@ -0,0 +1,45 @@
+use {
+    crate::col::ALL_COLS,
+    termimad::{
+        minimad::OwningTemplateExpander,
+        MadSkin,
+    },
+};
+
+static MD: &str = r#"
+The `--cols` launch argument lets you specify the columns of the **lfs** table.
+
+You can give the explicit list of all columns: `lfs -c dev+fs`
+
+You can add columns to the default ones: `lfs -c +dev+size`
+
+Complete syntax at https://dystroy.org/lfs/table
+
+|:-:|:-:|:-:|:-
+|column | aliases | default | content
+|:-:|:-:|:-:|-
+${column
+|${name}|${aliases}|${default}|${description}
+}
+|-
+"#;
+
+/// Print an help text describing columns
+pub fn print(color: bool) {
+    let mut expander = OwningTemplateExpander::new();
+    expander.set_default("");
+    for &col in ALL_COLS {
+        expander.sub("column")
+            .set("name", col.name())
+            .set("aliases", col.aliases().join(", "))
+            .set("default", if col.is_default() { "x" } else { "" })
+            .set("description", col.description());
+    }
+    let skin = if color {
+        MadSkin::default()
+    } else {
+        MadSkin::no_style()
+    };
+    skin.print_owning_expander_md(&expander, MD);
+}
+
diff --git a/src/main.rs b/src/main.rs
index 554f049..fd0eb9b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -2,12 +2,12 @@ mod args;
 mod col;
 mod cols;
 mod json;
+mod list_cols;
 mod table;
 mod units;
 
 use {
     crate::args::*,
-    crossterm::tty::IsTty,
     std::{
         cmp::Reverse,
         fs,
@@ -21,6 +21,10 @@ fn main() {
         println!("lfs {}", env!("CARGO_PKG_VERSION"));
         return;
     }
+    if args.list_cols {
+        list_cols::print(args.color());
+        return;
+    }
     let mut mounts = match lfs_core::read_mounts() {
         Ok(mounts) => mounts,
         Err(e) => {
@@ -60,9 +64,7 @@ fn main() {
         println!("no disk was found - try\n    lfs -a");
     } else {
         mounts.sort_by_key(|m| Reverse(m.size()));
-        let color = args.color.value()
-            .unwrap_or_else(|| std::io::stdout().is_tty());
-        table::print(&mounts, color, &args);
+        table::print(&mounts, args.color(), &args);
     }
 }
 
diff --git a/website/docs/table.md b/website/docs/table.md
index 5cefa65..a29a02a 100644
--- a/website/docs/table.md
+++ b/website/docs/table.md
@@ -4,6 +4,8 @@ You can modify it easily.
 
 # Columns
 
+You can run `lfs --list-cols` for the list of all columns.
+
 ## All columns
 
 name | default | meaning
@@ -26,6 +28,7 @@ inodes_use_percent |  | inodes use share, in percents
 inodescount |  | total number of inodes in the filesystem
 mount | ✓ | mounting path
 
+
 ## --cols argument
 
 With the `--cols` launch argument, shortened as `-c`, you can change the displayed columns or their order.