Allow parse-time evaluation of calls, pipelines and subexpressions (#9499)

Co-authored-by: Antoine Stevan <44101798+amtoine@users.noreply.github.com>

crates/nu-command/tests/commands/echo.rs

@@ -34,3 +34,9 @@ fn echo_range_handles_exclusive_down() {
 
     assert_eq!(actual.out, "[3,2]");
 }
+
+#[test]
+fn echo_const() {
+    let actual = nu!("const x = (echo spam); $x");
+    assert_eq!(actual.out, "spam");
+}

crates/nu-command/tests/commands/path/basename.rs

@@ -81,3 +81,9 @@ fn replaces_basename_of_path_ending_with_double_dot() {
     let expected = join_path_sep(&["some/file.txt/..", "eggs"]);
     assert_eq!(actual.out, expected);
 }
+
+#[test]
+fn const_path_basename() {
+    let actual = nu!("const name = ('spam/eggs.txt' | path basename); $name");
+    assert_eq!(actual.out, "eggs.txt");
+}

crates/nu-command/tests/commands/path/dirname.rs

@@ -135,3 +135,9 @@ fn replaces_dirname_of_way_too_many_levels() {
     let expected = join_path_sep(&["eggs", "some/dir/with/spam.txt"]);
     assert_eq!(actual.out, expected);
 }
+
+#[test]
+fn const_path_dirname() {
+    let actual = nu!("const name = ('spam/eggs.txt' | path dirname); $name");
+    assert_eq!(actual.out, "spam");
+}

crates/nu-command/tests/commands/path/exists.rs

@@ -57,3 +57,9 @@ fn checks_tilde_relative_path_exists() {
     let actual = nu!("'~' | path exists");
     assert_eq!(actual.out, "true");
 }
+
+#[test]
+fn const_path_exists() {
+    let actual = nu!("const exists = ('~' | path exists); $exists");
+    assert_eq!(actual.out, "true");
+}

crates/nu-command/tests/commands/path/expand.rs

@@ -66,6 +66,26 @@ fn expands_path_with_double_dot() {
     })
 }
 
+#[test]
+fn const_path_expand() {
+    Playground::setup("const_path_expand", |dirs, sandbox| {
+        sandbox
+            .within("menu")
+            .with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                const result = ("menu/./spam.txt" | path expand);
+                $result
+            "#
+        ));
+
+        let expected = dirs.test.join("menu").join("spam.txt");
+        assert_eq!(PathBuf::from(actual.out), expected);
+    })
+}
+
 #[cfg(windows)]
 mod windows {
     use super::*;

crates/nu-command/tests/commands/path/join.rs

@@ -54,3 +54,10 @@ fn returns_joined_path_when_joining_empty_path() {
 
     assert_eq!(actual.out, "foo.txt");
 }
+
+#[test]
+fn const_path_join() {
+    let actual = nu!("const name = ('spam' | path join 'eggs.txt'); $name");
+    let expected = join_path_sep(&["spam", "eggs.txt"]);
+    assert_eq!(actual.out, expected);
+}

crates/nu-command/tests/commands/path/mod.rs

@@ -7,6 +7,7 @@ mod parse;
 mod split;
 mod type_;
 
+use nu_test_support::{nu, pipeline};
 use std::path::MAIN_SEPARATOR;
 
 /// Helper function that joins string literals with '/' or '\', based on host OS
@@ -32,3 +33,9 @@ fn joins_path_on_other_than_windows() {
 
     assert_eq!(&actual, "sausage/bacon/spam");
 }
+
+#[test]
+fn const_path_relative_to() {
+    let actual = nu!("'/home/viking' | path relative-to '/home'");
+    assert_eq!(actual.out, "viking");
+}

crates/nu-command/tests/commands/path/parse.rs

@@ -119,3 +119,15 @@ fn parses_into_correct_number_of_columns() {
 
     assert_eq!(actual.out, expected);
 }
+
+#[test]
+fn const_path_parse() {
+    let actual = nu!("const name = ('spam/eggs.txt' | path parse); $name.parent");
+    assert_eq!(actual.out, "spam");
+
+    let actual = nu!("const name = ('spam/eggs.txt' | path parse); $name.stem");
+    assert_eq!(actual.out, "eggs");
+
+    let actual = nu!("const name = ('spam/eggs.txt' | path parse); $name.extension");
+    assert_eq!(actual.out, "txt");
+}

crates/nu-command/tests/commands/path/split.rs

@@ -25,3 +25,13 @@ fn splits_correctly_single_path() {
 
     assert_eq!(actual.out, "spam.txt");
 }
+
+#[test]
+fn splits_correctly_single_path_const() {
+    let actual = nu!(r#"
+        const result = ('home/viking/spam.txt' | path split);
+        $result | last
+    "#);
+
+    assert_eq!(actual.out, "spam.txt");
+}

crates/nu-command/tests/commands/path/type_.rs

@@ -61,3 +61,22 @@ fn returns_type_of_existing_directory() {
         assert_eq!(actual.out, "dir");
     })
 }
+
+#[test]
+fn returns_type_of_existing_file_const() {
+    Playground::setup("path_type_const", |dirs, sandbox| {
+        sandbox
+            .within("menu")
+            .with_files(vec![EmptyFile("spam.txt")]);
+
+        let actual = nu!(
+            cwd: dirs.test(), pipeline(
+            r#"
+                const ty = ("menu" | path type);
+                $ty
+            "#
+        ));
+
+        assert_eq!(actual.out, "dir");
+    })
+}