feat(fennel): add fennel module (#4717)

13 files changed, 273 insertions, 0 deletions

diff --git a/.github/config-schema.json b/.github/config-schema.json
index 404cdd6aa..e7fb0af12 100644
--- a/.github/config-schema.json
+++ b/.github/config-schema.json
@@ -473,6 +473,25 @@
         }
       ]
     },
+    "fennel": {
+      "default": {
+        "detect_extentions": [
+          "fnl"
+        ],
+        "detect_files": [],
+        "detect_folders": [],
+        "disabled": true,
+        "format": "via [$symbol($version )]($style)",
+        "style": "bold green",
+        "symbol": "🧅 ",
+        "version_format": "v${raw}"
+      },
+      "allOf": [
+        {
+          "$ref": "#/definitions/FennelConfig"
+        }
+      ]
+    },
     "fill": {
       "default": {
         "disabled": false,
@@ -2867,6 +2886,55 @@
       },
       "additionalProperties": false
     },
+    "FennelConfig": {
+      "type": "object",
+      "properties": {
+        "format": {
+          "default": "via [$symbol($version )]($style)",
+          "type": "string"
+        },
+        "version_format": {
+          "default": "v${raw}",
+          "type": "string"
+        },
+        "symbol": {
+          "default": "🧅 ",
+          "type": "string"
+        },
+        "style": {
+          "default": "bold green",
+          "type": "string"
+        },
+        "disabled": {
+          "default": true,
+          "type": "boolean"
+        },
+        "detect_extentions": {
+          "default": [
+            "fnl"
+          ],
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "detect_files": {
+          "default": [],
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "detect_folders": {
+          "default": [],
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        }
+      },
+      "additionalProperties": false
+    },
     "FillConfig": {
       "type": "object",
       "properties": {
diff --git a/docs/.vuepress/public/presets/toml/bracketed-segments.toml b/docs/.vuepress/public/presets/toml/bracketed-segments.toml
index c86ed0479..deaa6ae8c 100644
--- a/docs/.vuepress/public/presets/toml/bracketed-segments.toml
+++ b/docs/.vuepress/public/presets/toml/bracketed-segments.toml
@@ -46,6 +46,9 @@ format = '\[[$symbol($version)]($style)\]'
 [erlang]
 format = '\[[$symbol($version)]($style)\]'
 
+[fennel]
+format = '\[[$symbol($version)]($style)\]'
+
 [gcloud]
 format = '\[[$symbol$account(@$domain)(\($region\))]($style)\]'
 
diff --git a/docs/.vuepress/public/presets/toml/no-empty-icons.toml b/docs/.vuepress/public/presets/toml/no-empty-icons.toml
index 5b98fb7fb..eb94f1a31 100644
--- a/docs/.vuepress/public/presets/toml/no-empty-icons.toml
+++ b/docs/.vuepress/public/presets/toml/no-empty-icons.toml
@@ -37,6 +37,9 @@ format = '(via [$symbol($version )]($style))'
 [erlang]
 format = '(via [$symbol($version )]($style))'
 
+[fennel]
+format = '(via [$symbol($version )]($style))'
+
 [golang]
 format = '(via [$symbol($version )]($style))'
 
diff --git a/docs/.vuepress/public/presets/toml/no-runtime-versions.toml b/docs/.vuepress/public/presets/toml/no-runtime-versions.toml
index 97b6a3ed7..09accea7d 100644
--- a/docs/.vuepress/public/presets/toml/no-runtime-versions.toml
+++ b/docs/.vuepress/public/presets/toml/no-runtime-versions.toml
@@ -34,6 +34,9 @@ format = 'via [$symbol]($style)'
 [erlang]
 format = 'via [$symbol]($style)'
 
+[fennel]
+format = 'via [$symbol]($style)'
+
 [golang]
 format = 'via [$symbol]($style)'
 
diff --git a/docs/.vuepress/public/presets/toml/plain-text-symbols.toml b/docs/.vuepress/public/presets/toml/plain-text-symbols.toml
index 1efccd243..66eca654d 100644
--- a/docs/.vuepress/public/presets/toml/plain-text-symbols.toml
+++ b/docs/.vuepress/public/presets/toml/plain-text-symbols.toml
@@ -58,6 +58,9 @@ symbol = "exs "
 [elm]
 symbol = "elm "
 
+[fennel]
+symbol = "fnl "
+
 [git_branch]
 symbol = "git "
 
diff --git a/docs/config/README.md b/docs/config/README.md
index 5cd20bad1..904504b24 100644
--- a/docs/config/README.md
+++ b/docs/config/README.md
@@ -283,6 +283,7 @@ $dotnet\
 $elixir\
 $elm\
 $erlang\
+$fennel\
 $golang\
 $guix_shell\
 $haskell\
@@ -1475,6 +1476,45 @@ By default the module will be shown if any of the following conditions are met:
 format = 'via [e $version](bold red) '
 ```
 
+## Fennel
+
+The `fennel` module shows the currently installed version of [Fennel](https://fennel-lang.org).
+By default the module will be shown if any of the following conditions are met:
+
+- The current directory contains a file with the `.fnl` extension
+
+### Options
+
+| Option              | Default                              | Description                                                               |
+| ------------------- | ------------------------------------ | ------------------------------------------------------------------------- |
+| `format`            | `'via [$symbol($version )]($style)'` | The format for the module.                                                |
+| `version_format`    | `'v${raw}'`                          | The version format. Available vars are `raw`, `major`, `minor`, & `patch` |
+| `symbol`            | `'🧅 '`                              | The symbol used before displaying the version of fennel.                  |
+| `style`             | `'bold green'`                       | The style for the module.                                                 |
+| `detect_extensions` | `[fnl]`                              | Which extensions should trigger this module.                              |
+| `detect_files`      | `[]`                                 | Which filenames should trigger this module.                               |
+| `detect_folders`    | `[]`                                 | Which folders should trigger this modules.                                |
+| `disabled`          | `false`                              | Disables the `fennel` module.                                             |
+
+### Variables
+
+| Variable | Example  | Description                          |
+| -------- | -------- | ------------------------------------ |
+| version  | `v1.2.1` | The version of `fennel`              |
+| symbol   |          | Mirrors the value of option `symbol` |
+| style\*  |          | Mirrors the value of option `style`  |
+
+*: This variable can only be used as a part of a style string
+
+### Example
+
+```toml
+# ~/.config/starship.toml
+
+[fennel]
+symbol = '⫰ '
+```
+
 ## Fill
 
 The `fill` module fills any extra space on the line with a symbol. If multiple `fill` modules are
diff --git a/src/configs/fennel.rs b/src/configs/fennel.rs
new file mode 100644
index 000000000..e0564c9e6
--- /dev/null
+++ b/src/configs/fennel.rs
@@ -0,0 +1,34 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Deserialize, Serialize)]
+#[cfg_attr(
+    feature = "config-schema",
+    derive(schemars::JsonSchema),
+    schemars(deny_unknown_fields)
+)]
+#[serde(default)]
+pub struct FennelConfig<'a> {
+    pub format: &'a str,
+    pub version_format: &'a str,
+    pub symbol: &'a str,
+    pub style: &'a str,
+    pub disabled: bool,
+    pub detect_extentions: Vec<&'a str>,
+    pub detect_files: Vec<&'a str>,
+    pub detect_folders: Vec<&'a str>,
+}
+
+impl<'a> Default for FennelConfig<'a> {
+    fn default() -> Self {
+        FennelConfig {
+            format: "via [$symbol($version )]($style)",
+            version_format: "v${raw}",
+            symbol: "🧅 ",
+            style: "bold green",
+            disabled: true,
+            detect_extentions: vec!["fnl"],
+            detect_files: vec![],
+            detect_folders: vec![],
+        }
+    }
+}
diff --git a/src/configs/mod.rs b/src/configs/mod.rs
index 88d1d8d97..8a712e5fb 100644
--- a/src/configs/mod.rs
+++ b/src/configs/mod.rs
@@ -25,6 +25,7 @@ pub mod elixir;
 pub mod elm;
 pub mod env_var;
 pub mod erlang;
+pub mod fennel;
 pub mod fill;
 pub mod gcloud;
 pub mod git_branch;
@@ -149,6 +150,8 @@ pub struct FullConfig<'a> {
     #[serde(borrow)]
     erlang: erlang::ErlangConfig<'a>,
     #[serde(borrow)]
+    fennel: fennel::FennelConfig<'a>,
+    #[serde(borrow)]
     fill: fill::FillConfig<'a>,
     #[serde(borrow)]
     gcloud: gcloud::GcloudConfig<'a>,
diff --git a/src/configs/starship_root.rs b/src/configs/starship_root.rs
index 3fdd06f68..891e90746 100644
--- a/src/configs/starship_root.rs
+++ b/src/configs/starship_root.rs
@@ -57,6 +57,7 @@ pub const PROMPT_ORDER: &[&str] = &[
     "elixir",
     "elm",
     "erlang",
+    "fennel",
     "golang",
     "gradle",
     "haskell",
diff --git a/src/module.rs b/src/module.rs
index a2b2f1b28..77508f147 100644
--- a/src/module.rs
+++ b/src/module.rs
@@ -33,6 +33,7 @@ pub const ALL_MODULES: &[&str] = &[
     "elm",
     "env_var",
     "erlang",
+    "fennel",
     "fill",
     "gcloud",
     "git_branch",
diff --git a/src/modules/fennel.rs b/src/modules/fennel.rs
new file mode 100644
index 000000000..4b8a2fc98
--- /dev/null
+++ b/src/modules/fennel.rs
@@ -0,0 +1,107 @@
+use super::{Context, Module, ModuleConfig};
+
+use crate::configs::fennel::FennelConfig;
+use crate::formatter::{StringFormatter, VersionFormatter};
+use crate::utils::get_command_string_output;
+
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
+    let mut module = context.new_module("fennel");
+    let config = FennelConfig::try_load(module.config);
+
+    let is_fnl_project = context
+        .try_begin_scan()?
+        .set_files(&config.detect_files)
+        .set_extensions(&config.detect_extentions)
+        .set_folders(&config.detect_folders)
+        .is_match();
+
+    if !is_fnl_project {
+        return None;
+    }
+
+    let parsed = StringFormatter::new(config.format).and_then(|formatter| {
+        formatter
+            .map_meta(|var, _| match var {
+                "symbol" => Some(config.symbol),
+                _ => None,
+            })
+            .map_style(|variable| match variable {
+                "style" => Some(Ok(config.style)),
+                _ => None,
+            })
+            .map(|variable| match variable {
+                "version" => {
+                    let fennel_version_string =
+                        get_command_string_output(context.exec_cmd("fennel", &["--version"])?);
+                    let fennel_version = parse_fennel_version(&fennel_version_string)?;
+                    VersionFormatter::format_module_version(
+                        module.get_name(),
+                        &fennel_version,
+                        config.version_format,
+                    )
+                    .map(Ok)
+                }
+                _ => None,
+            })
+            .parse(None, Some(context))
+    });
+
+    module.set_segments(match parsed {
+        Ok(segments) => segments,
+        Err(error) => {
+            log::warn!("Error in module `fennel`:\n{}", error);
+            return None;
+        }
+    });
+
+    Some(module)
+}
+
+fn parse_fennel_version(fennel_version: &str) -> Option<String> {
+    // fennel -v output looks like this:
+    // Fennel 1.2.1 on PUC Lua 5.4
+    let version = fennel_version
+        // split into ["Fennel", "1.2.1", "on", ...]
+        .split_whitespace()
+        // take "1.2.1"
+        .nth(1)?;
+
+    Some(version.to_string())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test::ModuleRenderer;
+    use nu_ansi_term::Color;
+    use std::fs::File;
+    use std::io;
+
+    #[test]
+    fn folder_without_fennel_files() -> io::Result<()> {
+        let dir = tempfile::tempdir()?;
+        let actual = ModuleRenderer::new("fennel").path(dir.path()).collect();
+        let expected = None;
+        assert_eq!(expected, actual);
+        dir.close()
+    }
+
+    #[test]
+    fn folder_with_fennel_files() -> io::Result<()> {
+        let dir = tempfile::tempdir()?;
+        File::create(dir.path().join("man.fnl"))?.sync_all()?;
+        let actual = ModuleRenderer::new("fennel").path(dir.path()).collect();
+        let expected = Some(format!("via {}", Color::Green.bold().paint("🧅 v1.2.1 ")));
+        assert_eq!(expected, actual);
+        dir.close()
+    }
+
+    #[test]
+    fn test_parse_fennel_version() {
+        let fennel_input = "Fennel 1.2.1 on PUC Lua 5.4";
+        assert_eq!(
+            parse_fennel_version(fennel_input),
+            Some("1.2.1".to_string())
+        );
+    }
+}
diff --git a/src/modules/mod.rs b/src/modules/mod.rs
index e9117054d..8c8c5b6bb 100644
--- a/src/modules/mod.rs
+++ b/src/modules/mod.rs
@@ -22,6 +22,7 @@ mod elixir;
 mod elm;
 mod env_var;
 mod erlang;
+mod fennel;
 mod fill;
 mod gcloud;
 mod git_branch;
@@ -121,6 +122,7 @@ pub fn handle<'a>(module: &str, context: &'a Context) -> Option<Module<'a>> {
             "elixir" => elixir::module(context),
             "elm" => elm::module(context),
             "erlang" => erlang::module(context),
+            "fennel" => fennel::module(context),
             "env_var" => env_var::module(context),
             "fill" => fill::module(context),
             "gcloud" => gcloud::module(context),
@@ -233,6 +235,7 @@ pub fn description(module: &str) -> &'static str {
         "elm" => "The currently installed version of Elm",
         "env_var" => "Displays the current value of a selected environment variable",
         "erlang" => "Current OTP version",
+        "fennel" => "The currently installed version of Fennel",
         "fill" => "Fills the remaining space on the line with a pad string",
         "gcloud" => "The current GCP client configuration",
         "git_branch" => "The active branch of the repo in your current directory",
diff --git a/src/utils.rs b/src/utils.rs
index 06a5c2701..1d035daca 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -245,6 +245,10 @@ Elixir 1.10 (compiled with Erlang/OTP 22)\n",
             stdout: String::from("0.19.1\n"),
             stderr: String::default(),
         }),
+        "fennel --version" => Some(CommandOutput {
+            stdout: String::from("Fennel 1.2.1 on PUC Lua 5.4\n"),
+            stderr: String::default(),
+        }),
         "go version" => Some(CommandOutput {
             stdout: String::from("go version go1.12.1 linux/amd64\n"),
             stderr: String::default(),