Improve support for variable prompt in shell scripting (#428)

Cargo.lock

@@ -196,7 +196,7 @@ checksum = "3728d817d99e5ac407411fa471ff9800a778d88a24685968b36824eaf4bee400"
 
 [[package]]
 name = "navi"
-version = "2.12.2"
+version = "2.13.0"
 dependencies = [
  "anyhow",
  "directories-next",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "navi"
-version = "2.12.2"
+version = "2.13.0"
 authors = ["Denis Isidoro <denis_isidoro@live.com>"]
 edition = "2018"
 description = "An interactive cheatsheet tool for the command-line"

docs/shell_scripting.md

@@ -10,7 +10,23 @@ navi --query "change branch" --best-match
 
 **navi** will ask the user to fill all arguments needed. 
 
-If you want to set the `<branch>` beforehand in your script, you could then write:
+If you want to set the `<branch>` beforehand in your script:
 ```sh
 branch="master" navi --query "change branch" --best-match
 ```
+- no interactive input will be shown
+- the value for `<branch>` will be exactly the one passed as argument
+
+If you want to filter some results for `<branch>`:
+```sh
+branch__query="master" navi --query "change branch" --best-match
+```
+- an interactive input will be shown, unless a single entry is autoselected
+- the value for `<branch>` will be the one selected
+
+If you want to select the best match for `<branch>`:
+```sh
+branch__best="master" navi --query "change branch" --best-match
+```
+- no interactive input will be shown
+- the value for `<branch>` will be the one that best matches the one passed as argument

src/cmds/core.rs

@@ -40,10 +40,10 @@ fn gen_core_finder_opts(config: &Config) -> Result<FinderOpts, Error> {
 
 fn extract_from_selections(raw_snippet: &str, is_single: bool) -> Result<(&str, &str, &str, &str), Error> {
     let mut lines = raw_snippet.split('\n');
-    let key = if !is_single {
-        lines.next().context("Key was promised but not present in `selections`")?
-    } else {
+    let key = if is_single {
         "enter"
+    } else {
+        lines.next().context("Key was promised but not present in `selections`")?
     };
 
     let mut parts = lines.next().context("No more parts in `selections`")?.split(display::DELIMITER).skip(3);
@@ -113,6 +113,13 @@ NAVIEOF
         ..opts.clone().unwrap_or_default()
     };
 
+    opts.query = env::var(format!("{}__query", variable_name)).ok();
+
+    if let Ok(f) = env::var(format!("{}__best", variable_name)) {
+        opts.filter = Some(f);
+        opts.suggestion_type = SuggestionType::SingleSelection;
+    }
+
     if opts.preview_window.is_none() {
         opts.preview_window = Some(if extra_preview.is_none() {
             format!("up:{}", variable_count + 3)