Add pager option for customizing pager without environment variables (#627)

* Add pager option

* Use config.pager for output

5 files changed, 17 insertions, 8 deletions

diff --git a/src/bat_utils/output.rs b/src/bat_utils/output.rs
index 388bc0c9..1166b4e2 100644
--- a/src/bat_utils/output.rs
+++ b/src/bat_utils/output.rs
@@ -29,7 +29,7 @@ pub enum OutputType {
 impl OutputType {
     pub fn from_mode(
         mode: PagingMode,
-        pager: Option<&str>,
+        pager: Option<String>,
         config: &config::Config,
     ) -> Result<Self> {
         use self::PagingMode::*;
@@ -43,7 +43,7 @@ impl OutputType {
     /// Try to launch the pager. Fall back to stdout in case of errors.
     fn try_pager(
         quit_if_one_screen: bool,
-        pager_from_config: Option<&str>,
+        pager_from_config: Option<String>,
         config: &config::Config,
     ) -> Result<Self> {
         let mut replace_arguments_to_less = false;
@@ -66,8 +66,6 @@ impl OutputType {
             _ => None,
         };
 
-        let pager_from_config = pager_from_config.map(|p| p.to_string());
-
         if pager_from_config.is_some() {
             replace_arguments_to_less = false;
         }
diff --git a/src/cli.rs b/src/cli.rs
index d9873d3c..72e91b5a 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -532,9 +532,14 @@ pub struct Opt {
     #[structopt(long = "inspect-raw-lines", default_value = "true")]
     pub inspect_raw_lines: String,
 
-    /// Whether to use a pager when displaying output. Options are: auto, always, and never. The
-    /// default pager is `less`: this can be altered by setting the environment variables
-    /// DELTA_PAGER, BAT_PAGER, or PAGER (and that is their order of priority).
+    #[structopt(long)]
+    /// Which pager to use. The default pager is `less`. You can also change pager
+    /// by setting the environment variables DELTA_PAGER, BAT_PAGER, or PAGER
+    /// (and that is their order of priority). This option overrides all environment
+    /// variables above.
+    pub pager: Option<String>,
+
+    /// Whether to use a pager when displaying output. Options are: auto, always, and never.
     #[structopt(long = "paging", default_value = "auto")]
     pub paging_mode: String,
 
diff --git a/src/config.rs b/src/config.rs
index 0b8ab6d1..573a08ed 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -66,6 +66,7 @@ pub struct Config {
     pub navigate_regexp: Option<String>,
     pub null_style: Style,
     pub null_syntect_style: SyntectStyle,
+    pub pager: Option<String>,
     pub paging_mode: PagingMode,
     pub plus_emph_style: Style,
     pub plus_empty_line_marker_style: Style,
@@ -246,6 +247,7 @@ impl From<cli::Opt> for Config {
             navigate_regexp,
             null_style: Style::new(),
             null_syntect_style: SyntectStyle::default(),
+            pager: opt.pager,
             paging_mode: opt.computed.paging_mode,
             plus_emph_style,
             plus_empty_line_marker_style,
diff --git a/src/main.rs b/src/main.rs
index cbeb0bcf..d6ed0aa2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -82,7 +82,8 @@ fn run_app() -> std::io::Result<i32> {
         return Ok(0);
     }
 
-    let mut output_type = OutputType::from_mode(config.paging_mode, None, &config).unwrap();
+    let mut output_type =
+        OutputType::from_mode(config.paging_mode, config.pager.clone(), &config).unwrap();
     let mut writer = output_type.handle().unwrap();
 
     if atty::is(atty::Stream::Stdin) {
@@ -246,6 +247,7 @@ fn show_config(config: &config::Config, writer: &mut dyn Write) -> std::io::Resu
     max-line-length               = {max_line_length}
     navigate                      = {navigate}
     navigate-regexp               = {navigate_regexp}
+    pager                         = {pager}
     paging                        = {paging_mode}
     side-by-side                  = {side_by_side}
     syntax-theme                  = {syntax_theme}
@@ -259,6 +261,7 @@ fn show_config(config: &config::Config, writer: &mut dyn Write) -> std::io::Resu
             None => "".to_string(),
             Some(s) => s.to_string(),
         },
+        pager = config.pager.clone().unwrap_or_else(|| "none".to_string()),
         paging_mode = match config.paging_mode {
             PagingMode::Always => "always",
             PagingMode::Never => "never",
diff --git a/src/options/set.rs b/src/options/set.rs
index a737fd4b..ef0a259c 100644
--- a/src/options/set.rs
+++ b/src/options/set.rs
@@ -165,6 +165,7 @@ pub fn set_options(
             line_numbers_right_format,
             line_numbers_right_style,
             line_numbers_zero_style,
+            pager,
             paging_mode,
             // Hack: plus-style must come before plus-*emph-style because the latter default
             // dynamically to the value of the former.