1 files changed, 136 insertions, 0 deletions
diff --git a/src/shells/elvish.rs b/src/shells/elvish.rs
new file mode 100644
index 0000000..48a0f85
--- /dev/null
+++ b/src/shells/elvish.rs
@@ -0,0 +1,136 @@
+use std::io::Write;
+
+use clap::builder::StyledStr;
+use clap::*;
+
+use crate::generator::{utils, Generator};
+use crate::INTERNAL_ERROR_MSG;
+
+/// Generate elvish completion file
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub struct Elvish;
+
+impl Generator for Elvish {
+    fn file_name(&self, name: &str) -> String {
+        format!("{name}.elv")
+    }
+
+    fn generate(&self, cmd: &Command, buf: &mut dyn Write) {
+        let bin_name = cmd
+            .get_bin_name()
+            .expect("crate::generate should have set the bin_name");
+
+        let subcommands_cases = generate_inner(cmd, "");
+
+        let result = format!(
+            r#"
+use builtin;
+use str;
+
+set edit:completion:arg-completer[{bin_name}] = {{|@words|
+    fn spaces {{|n|
+        builtin:repeat $n ' ' | str:join ''
+    }}
+    fn cand {{|text desc|
+        edit:complex-candidate $text &display=$text' '(spaces (- 14 (wcswidth $text)))$desc
+    }}
+    var command = '{bin_name}'
+    for word $words[1..-1] {{
+        if (str:has-prefix $word '-') {{
+            break
+        }}
+        set command = $command';'$word
+    }}
+    var completions = [{subcommands_cases}
+    ]
+    $completions[$command]
+}}
+"#,
+        );
+
+        w!(buf, result.as_bytes());
+    }
+}
+
+// Escape string inside single quotes
+fn escape_string(string: &str) -> String {
+    string.replace('\'', "''")
+}
+
+fn get_tooltip<T: ToString>(help: Option<&StyledStr>, data: T) -> String {
+    match help {
+        Some(help) => escape_string(&help.to_string()),
+        _ => data.to_string(),
+    }
+}
+
+fn generate_inner(p: &Command, previous_command_name: &str) -> String {
+    debug!("generate_inner");
+
+    let command_name = if previous_command_name.is_empty() {
+        p.get_bin_name().expect(INTERNAL_ERROR_MSG).to_string()
+    } else {
+        format!("{};{}", previous_command_name, &p.get_name())
+    };
+
+    let mut completions = String::new();
+    let preamble = String::from("\n            cand ");
+
+    for option in p.get_opts() {
+        if let Some(shorts) = option.get_short_and_visible_aliases() {
+            let tooltip = get_tooltip(option.get_help(), shorts[0]);
+            for short in shorts {
+                completions.push_str(&preamble);
+                completions.push_str(format!("-{short} '{tooltip}'").as_str());
+            }
+        }
+
+        if let Some(longs) = option.get_long_and_visible_aliases() {
+            let tooltip = get_tooltip(option.get_help(), longs[0]);
+            for long in longs {
+                completions.push_str(&preamble);
+                completions.push_str(format!("--{long} '{tooltip}'").as_str());
+            }
+        }
+    }
+
+    for flag in utils::flags(p) {
+        if let Some(shorts) = flag.get_short_and_visible_aliases() {
+            let tooltip = get_tooltip(flag.get_help(), shorts[0]);
+            for short in shorts {
+                completions.push_str(&preamble);
+                completions.push_str(format!("-{short} '{tooltip}'").as_str());
+            }
+        }
+
+        if let Some(longs) = flag.get_long_and_visible_aliases() {
+            let tooltip = get_tooltip(flag.get_help(), longs[0]);
+            for long in longs {
+                completions.push_str(&preamble);
+                completions.push_str(format!("--{long} '{tooltip}'").as_str());
+            }
+        }
+    }
+
+    for subcommand in p.get_subcommands() {
+        let data = &subcommand.get_name();
+        let tooltip = get_tooltip(subcommand.get_about(), data);
+
+        completions.push_str(&preamble);
+        completions.push_str(format!("{data} '{tooltip}'").as_str());
+    }
+
+    let mut subcommands_cases = format!(
+        r"
+        &'{}'= {{{}
+        }}",
+        &command_name, completions
+    );
+
+    for subcommand in p.get_subcommands() {
+        let subcommand_subcommands_cases = generate_inner(subcommand, &command_name);
+        subcommands_cases.push_str(&subcommand_subcommands_cases);
+    }
+
+    subcommands_cases
+}