Add const to some new functions. (#555)

* Add const to some new functions.

* Add const to SearchFilter builders.

* Add const to SearchQuery builders.

src/core_editor/editor.rs

@@ -27,7 +27,7 @@ impl Default for Editor {
 
 impl Editor {
     /// Get the current [`LineBuffer`]
-    pub fn line_buffer(&self) -> &LineBuffer {
+    pub const fn line_buffer(&self) -> &LineBuffer {
         &self.line_buffer
     }
 

src/edit_mode/emacs.rs

@@ -162,7 +162,7 @@ impl EditMode for Emacs {
 
 impl Emacs {
     /// Emacs style input parsing constructor if you want to use custom keybindings
-    pub fn new(keybindings: Keybindings) -> Self {
+    pub const fn new(keybindings: Keybindings) -> Self {
         Emacs { keybindings }
     }
 }

src/history/base.rs

@@ -54,6 +54,7 @@ pub struct SearchFilter {
     /// Filter whether the command completed
     pub exit_successful: Option<bool>,
 }
+
 impl SearchFilter {
     /// Create a search filter with a [`CommandLineSearch`]
     pub fn from_text_search(cmd: CommandLineSearch) -> SearchFilter {
@@ -61,8 +62,9 @@ impl SearchFilter {
         s.command_line = Some(cmd);
         s
     }
+
     /// No filter constraint
-    pub fn anything() -> SearchFilter {
+    pub const fn anything() -> SearchFilter {
         SearchFilter {
             command_line: None,
             not_command_line: None,
@@ -106,8 +108,9 @@ impl SearchQuery {
             filter: SearchFilter::from_text_search(CommandLineSearch::Substring(contains)),
         }
     }
+
     /// Get the most recent entry matching [`SearchFilter`]
-    pub fn last_with_search(filter: SearchFilter) -> SearchQuery {
+    pub const fn last_with_search(filter: SearchFilter) -> SearchQuery {
         SearchQuery {
             direction: SearchDirection::Backward,
             start_time: None,
@@ -118,14 +121,16 @@ impl SearchQuery {
             filter,
         }
     }
+
     /// Get the most recent entry starting with the `prefix`
     pub fn last_with_prefix(prefix: String) -> SearchQuery {
         SearchQuery::last_with_search(SearchFilter::from_text_search(CommandLineSearch::Prefix(
             prefix,
         )))
     }
+
     /// Query to get all entries in the given [`SearchDirection`]
-    pub fn everything(direction: SearchDirection) -> SearchQuery {
+    pub const fn everything(direction: SearchDirection) -> SearchQuery {
         SearchQuery {
             direction,
             start_time: None,

src/history/cursor.rs

@@ -16,7 +16,7 @@ pub struct HistoryCursor {
 }
 
 impl HistoryCursor {
-    pub fn new(query: HistoryNavigationQuery) -> HistoryCursor {
+    pub const fn new(query: HistoryNavigationQuery) -> HistoryCursor {
         HistoryCursor {
             query,
             current: None,

src/history/item.rs

@@ -6,7 +6,7 @@ use std::{fmt::Display, time::Duration};
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub struct HistoryItemId(pub(crate) i64);
 impl HistoryItemId {
-    pub(crate) fn new(i: i64) -> HistoryItemId {
+    pub(crate) const fn new(i: i64) -> HistoryItemId {
         HistoryItemId(i)
     }
 }
@@ -21,7 +21,7 @@ impl Display for HistoryItemId {
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub struct HistorySessionId(pub(crate) i64);
 impl HistorySessionId {
-    pub(crate) fn new(i: i64) -> HistorySessionId {
+    pub(crate) const fn new(i: i64) -> HistorySessionId {
         HistorySessionId(i)
     }
 }

src/painting/styled_text.rs

@@ -18,7 +18,7 @@ impl Default for StyledText {
 
 impl StyledText {
     /// Construct a new `StyledText`
-    pub fn new() -> Self {
+    pub const fn new() -> Self {
         Self { buffer: vec![] }
     }
 

src/prompt/base.rs

@@ -34,7 +34,7 @@ pub struct PromptHistorySearch {
 
 impl PromptHistorySearch {
     /// A constructor to create a history search
-    pub fn new(status: PromptHistorySearchStatus, search_term: String) -> Self {
+    pub const fn new(status: PromptHistorySearchStatus, search_term: String) -> Self {
         PromptHistorySearch {
             status,
             term: search_term,

src/prompt/default.rs

@@ -104,7 +104,7 @@ impl DefaultPrompt {
     /// Constructor for the default prompt, which takes a configurable left and right prompt.
     /// For less customization, use [`DefaultPrompt::default`].
     /// For more fine-tuned configuration, implement the [`Prompt`] trait.
-    pub fn new(
+    pub const fn new(
         left_prompt: DefaultPromptSegment,
         right_prompt: DefaultPromptSegment,
     ) -> DefaultPrompt {