feat: Add configuration for reordering the prompt module and disabling default order (#171)

Adds functionality for reordering the prompt module through the use of the prompt_order configuration option in starship.toml

3 files changed, 102 insertions, 5 deletions

diff --git a/docs/config/README.md b/docs/config/README.md
index 8f2697fb4..46bda21bf 100644
--- a/docs/config/README.md
+++ b/docs/config/README.md
@@ -46,9 +46,10 @@ This is the list of prompt-wide configuration options.
 
 ### Options
 
-| Variable      | Default | Description                                    |
-| ------------- | ------- | ---------------------------------------------- |
-| `add_newline` | `true`  | Add a new line before the start of the prompt. |
+| Variable       | Default | Description                                                        |
+| -------------- | ------- | ------------------------------------------------------------------ |
+| `add_newline`  | `true`  | Add a new line before the start of the prompt.                     |
+| `prompt_order` | [link](#default-prompt-order) | Configure the order in which the prompt module occurs. |
 
 ### Example
 
@@ -57,8 +58,32 @@ This is the list of prompt-wide configuration options.
 
 # Disable the newline at the start of the prompt
 add_newline = false
+# Overwrite a default_prompt_order and  use custom prompt_order
+prompt_order=["rust","line_break","package","line_break","character"]
 ```
 
+### Default prompt order
+The ```default_prompt_order``` configuration option is used to define the order in which modules are shown in the prompt, if empty or no ```prompt_order``` is provided. The default is as shown:
+```
+default_prompt_order = [
+    "username",
+    "directory",
+    "git_branch",
+    "git_status",
+    "package",
+    "nodejs",
+    "rust",
+    "python",
+    "golang",
+    "cmd_duration",
+    "line_break",
+    "jobs",
+    "battery",
+    "character",
+]
+```
+
+
 ## Battery
 
 The `battery` module shows how charged the device's battery is and its current charging status.
diff --git a/src/config.rs b/src/config.rs
index ba339468b..c51c37bce 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -13,6 +13,7 @@ pub trait Config {
     fn get_as_bool(&self, key: &str) -> Option<bool>;
     fn get_as_str(&self, key: &str) -> Option<&str>;
     fn get_as_i64(&self, key: &str) -> Option<i64>;
+    fn get_as_array(&self, key: &str) -> Option<&Vec<toml::value::Value>>;
 
     // Internal implementation for accessors
     fn get_config(&self, key: &str) -> Option<&toml::value::Value>;
@@ -141,6 +142,21 @@ impl Config for Table {
 
         i64_value
     }
+
+    /// Get a key from a module's configuration as a vector
+    fn get_as_array(&self, key: &str) -> Option<&Vec<toml::value::Value>> {
+        let value = self.get_config(key)?;
+        let array_value = value.as_array();
+        if array_value.is_none() {
+            log::debug!(
+                "Expected \"{}\" to be a array. Instead received {} of type {}.",
+                key,
+                value,
+                value.type_str()
+            );
+        }
+        array_value
+    }
 }
 
 #[cfg(test)]
diff --git a/src/print.rs b/src/print.rs
index 918d3f19d..0cf495f72 100644
--- a/src/print.rs
+++ b/src/print.rs
@@ -7,7 +7,29 @@ use crate::context::Context;
 use crate::module::Module;
 use crate::modules;
 
-const PROMPT_ORDER: &[&str] = &[
+// List of all modules
+const ALL_MODULES: &[&str] = &[
+    "battery",
+    "character",
+    "cmd_duration",
+    "directory",
+    "git_branch",
+    "git_status",
+    "golang",
+    "jobs",
+    "line_break",
+    "nodejs",
+    "package",
+    "python",
+    "ruby",
+    "rust",
+    "username",
+];
+
+// List of default prompt order
+// NOTE: If this const value is changed then Default prompt order subheading inside
+// prompt heading of config docs needs to be updated according to changes made here.
+const DEFAULT_PROMPT_ORDER: &[&str] = &[
     "username",
     "directory",
     "git_branch",
@@ -36,7 +58,41 @@ pub fn prompt(args: ArgMatches) {
         writeln!(handle).unwrap();
     }
 
-    let modules = PROMPT_ORDER
+    let mut prompt_order: Vec<&str> = Vec::new();
+
+    // Write out a custom prompt order
+    if let Some(modules) = config.get_as_array("prompt_order") {
+        // if prompt_order = [] use default_prompt_order
+        if !modules.is_empty() {
+            for module in modules {
+                let str_value = module.as_str();
+
+                if let Some(value) = str_value {
+                    if ALL_MODULES.contains(&value) {
+                        prompt_order.push(value);
+                    } else {
+                        log::debug!(
+                            "Expected prompt_order to contain value from {:?}. Instead received {}",
+                            ALL_MODULES,
+                            value,
+                        );
+                    }
+                } else {
+                    log::debug!(
+                        "Expected prompt_order to be an array of strings. Instead received {} of type {}",
+                        module,
+                        module.type_str()
+                    );
+                }
+            }
+        } else {
+            prompt_order = DEFAULT_PROMPT_ORDER.to_vec();
+        }
+    } else {
+        prompt_order = DEFAULT_PROMPT_ORDER.to_vec();
+    }
+
+    let modules = &prompt_order
         .par_iter()
         .map(|module| modules::handle(module, &context)) // Compute modules
         .flatten()