WIP

clap_complete/Cargo.toml

@@ -36,6 +36,10 @@ bench = false
 
 [dependencies]
 clap = { path = "../", version = "3.1.10", default-features = false, features = ["std"] }
+clap_lex = { path = "../clap_lex", version = "0.1.0", optional = true }
+os_str_bytes = { version = "6.0", default-features = false, features = ["raw_os_str"], optional = true }
+shlex = { version = "1.1.0", optional = true }
+unicode-xid = { version = "0.2.2", optional = true }
 
 [dev-dependencies]
 pretty_assertions = "1.0"
@@ -44,6 +48,7 @@ clap = { path = "../", version = "3.1.10", default-features = false, features =
 
 [features]
 default = []
+unstable-dynamic = ["clap_lex", "shlex", "unicode-xid", "os_str_bytes"]
 debug = ["clap/debug"]
 
 [package.metadata.docs.rs]

clap_complete/src/dynamic.rs

@@ -0,0 +1,140 @@
+//! Complete commands within shells
+
+/// Complete commands within bash
+pub mod bash {
+    use std::io::Write;
+    use unicode_xid::UnicodeXID;
+
+    /// The recommended file name for the registration code
+    pub fn file_name(name: &str) -> String {
+        format!("{}.bash", name)
+    }
+
+    /// Define the completion behavior
+    pub enum Behavior {
+        /// Bare bones behavior
+        Minimal,
+        /// Fallback to readline behavior when no matches are generated
+        Readline,
+        /// Customize bash's completion behavior
+        Custom(String),
+    }
+
+    /// Generate code to register the dynamic completion
+    pub fn register(
+        name: &str,
+        executables: impl IntoIterator<Item = impl AsRef<str>>,
+        completer: &str,
+        behavior: &Behavior,
+        buf: &mut dyn Write,
+    ) -> Result<(), std::io::Error> {
+        let escaped_name = name.replace("-", "_");
+        debug_assert!(
+            escaped_name.chars().all(|c| c.is_xid_continue()),
+            "`name` must be an identifier, got `{}`",
+            escaped_name
+        );
+        let mut upper_name = escaped_name.clone();
+        upper_name.make_ascii_uppercase();
+
+        let executables = executables
+            .into_iter()
+            .map(|s| shlex::quote(s.as_ref()).into_owned())
+            .collect::<Vec<_>>()
+            .join(" ");
+
+        let options = match behavior {
+            Behavior::Minimal => "-o nospace -o bashdefault",
+            Behavior::Readline => "-o nospace -o default -o bashdefault",
+            Behavior::Custom(c) => c.as_str(),
+        };
+
+        let completer = shlex::quote(completer);
+
+        let script = r#"
+# Run something, muting output or redirecting it to the debug stream
+# depending on the value of _ARC_DEBUG.
+# If UPPER_COMPLETE_USE_TEMPFILES is set, use tempfiles for IPC.
+__clap_complete_run_NAME() {
+    if [[ -z "${UPPER_COMPLETE_USE_TEMPFILES-}" ]]; then
+        __clap_complete_run_inner_NAME "$@"
+        return
+    fi
+    local tmpfile="$(mktemp)"
+    CLAP_COMPLETE_STDOUT_FILE="$tmpfile" __clap_complete_run_inner_NAME "$@"
+    local code=$?
+    cat "$tmpfile"
+    rm "$tmpfile"
+    return $code
+}
+__clap_complete_run_inner_NAME() {
+    if [[ -z "${_ARC_DEBUG-}" ]]; then
+        "$@" 8>&1 9>&2 1>/dev/null 2>&1
+    else
+        "$@" 8>&1 9>&2 1>&9 2>&1
+    fi
+}
+_clap_complete_NAME() {
+    local IFS=$'\013'
+    local SUPPRESS_SPACE=0
+    if compopt +o nospace 2> /dev/null; then
+        SUPPRESS_SPACE=1
+    fi
+    COMPREPLY=( $(IFS="$IFS" \
+                  COMP_LINE="$COMP_LINE" \
+                  COMP_POINT="$COMP_POINT" \
+                  COMP_TYPE="$COMP_TYPE" \
+                  CLAP_COMPLETE_COMP_WORDBREAKS="$COMP_WORDBREAKS" \
+                  CLAP_COMPLETE=1 \
+                  CLAP_COMPLETE_SUPPRESS_SPACE=$SUPPRESS_SPACE \
+                  __clap_complete_run_NAME COMPLETER) )
+    if [[ $? != 0 ]]; then
+        unset COMPREPLY
+    elif [[ $SUPPRESS_SPACE == 1 ]] && [[ "${COMPREPLY-}" =~ [=/:]$ ]]; then
+        compopt -o nospace
+    fi
+}
+complete OPTIONS -F _clap_complete_NAME EXECUTABLES
+"#
+        .replace("NAME", &escaped_name)
+        .replace("EXECUTABLES", &executables)
+        .replace("OPTIONS", options)
+        .replace("COMPLETER", &completer)
+        .replace("UPPER", &upper_name);
+
+        writeln!(buf, "{}", script)?;
+        Ok(())
+    }
+
+    /// Complete the command specified by env setup by [`register`]
+    pub fn complete_env(buf: &mut dyn Write) -> Result<(), std::io::Error> {
+        let comp_line = std::env::var_os("COMP_LINE")
+            .ok_or_else(|| std::io::Error::new(std::io::ErrorKind::Other, "`COMP_LINE` not set"))?;
+        let comp_point = std::env::var_os("COMP_POINT").ok_or_else(|| {
+            std::io::Error::new(std::io::ErrorKind::Other, "`COMP_POINT` not set")
+        })?;
+        let comp_point = comp_point.to_str().ok_or_else(|| {
+            std::io::Error::new(std::io::ErrorKind::Other, "`COMP_POINT` format is invalid")
+        })?;
+        let comp_point = comp_point.parse::<usize>().map_err(|e| {
+            std::io::Error::new(
+                std::io::ErrorKind::Other,
+                format!("`COMP_POINT` format is invalid: {}", e),
+            )
+        })?;
+        complete(&comp_line, comp_point, buf)?;
+        Ok(())
+    }
+
+    /// Complete the command specified
+    pub fn complete(
+        comp_line: &std::ffi::OsStr,
+        comp_point: usize,
+        _buf: &mut dyn Write,
+    ) -> Result<(), std::io::Error> {
+        let comp_line_raw = os_str_bytes::RawOsStr::new(comp_line);
+        let comp_line_bytes = comp_line_raw.as_raw_bytes();
+        let _comp_line_prefix_bytes = comp_line_bytes.get(..comp_point).unwrap_or(comp_line_bytes);
+        Ok(())
+    }
+}

clap_complete/src/lib.rs

@@ -68,3 +68,6 @@ pub use generator::generate;
 pub use generator::generate_to;
 pub use generator::Generator;
 pub use shells::Shell;
+
+#[cfg(feature = "unstable-dynamic")]
+pub mod dynamic;

clap_complete/tests/bash.rs

@@ -83,3 +83,19 @@ fn value_hint() {
         name,
     );
 }
+
+#[cfg(feature = "unstable-dynamic")]
+#[test]
+fn register_minimal() {
+    let name = "my-app";
+    let executables = [name];
+    let completer = name;
+    let behavior = clap_complete::dynamic::bash::Behavior::Minimal;
+
+    let mut buf = Vec::new();
+    clap_complete::dynamic::bash::register(name, executables, completer, &behavior, &mut buf)
+        .unwrap();
+    snapbox::Assert::new()
+        .action_env("SNAPSHOTS")
+        .matches_path("tests/snapshots/register_minimal.bash", buf);
+}

clap_complete/tests/snapshots/register_minimal.bash

@@ -0,0 +1,45 @@
+
+# Run something, muting output or redirecting it to the debug stream
+# depending on the value of _ARC_DEBUG.
+# If MY_APP_COMPLETE_USE_TEMPFILES is set, use tempfiles for IPC.
+__clap_complete_run_my_app() {
+    if [[ -z "${MY_APP_COMPLETE_USE_TEMPFILES-}" ]]; then
+        __clap_complete_run_inner_my_app "$@"
+        return
+    fi
+    local tmpfile="$(mktemp)"
+    CLAP_COMPLETE_STDOUT_FILE="$tmpfile" __clap_complete_run_inner_my_app "$@"
+    local code=$?
+    cat "$tmpfile"
+    rm "$tmpfile"
+    return $code
+}
+__clap_complete_run_inner_my_app() {
+    if [[ -z "${_ARC_DEBUG-}" ]]; then
+        "$@" 8>&1 9>&2 1>/dev/null 2>&1
+    else
+        "$@" 8>&1 9>&2 1>&9 2>&1
+    fi
+}
+_clap_complete_my_app() {
+    local IFS=$'/013'
+    local SUPPRESS_SPACE=0
+    if compopt +o nospace 2> /dev/null; then
+        SUPPRESS_SPACE=1
+    fi
+    COMPREPLY=( $(IFS="$IFS" /
+                  COMP_LINE="$COMP_LINE" /
+                  COMP_POINT="$COMP_POINT" /
+                  COMP_TYPE="$COMP_TYPE" /
+                  CLAP_COMPLETE_COMP_WORDBREAKS="$COMP_WORDBREAKS" /
+                  CLAP_COMPLETE=1 /
+                  CLAP_COMPLETE_SUPPRESS_SPACE=$SUPPRESS_SPACE /
+                  __clap_complete_run_my_app my-app) )
+    if [[ $? != 0 ]]; then
+        unset COMPREPLY
+    elif [[ $SUPPRESS_SPACE == 1 ]] && [[ "${COMPREPLY-}" =~ [=/:]$ ]]; then
+        compopt -o nospace
+    fi
+}
+complete -o nospace -o bashdefault -F _clap_complete_my_app my-app
+