Math operators (#1601)

* Add some math operations

* WIP for adding compound expressions

* precedence parsing

* paren expressions

* better lhs handling

* add compound comparisons and shorthand lefthand parsing

* Add or comparison and shorthand paths

crates/nu-cli/tests/commands/math.rs

@@ -0,0 +1,133 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn one_arg() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            = 1
+        "#
+    ));
+
+    assert_eq!(actual, "1");
+}
+
+#[test]
+fn add() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            = 1 + 1
+        "#
+    ));
+
+    assert_eq!(actual, "2");
+}
+
+#[test]
+fn add_compount() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            = 1 + 2 + 2
+        "#
+    ));
+
+    assert_eq!(actual, "5");
+}
+
+#[test]
+fn precedence_of_operators() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            = 1 + 2 * 2
+        "#
+    ));
+
+    assert_eq!(actual, "5");
+}
+
+#[test]
+fn precedence_of_operators2() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            = 1 + 2 * 2 + 1
+        "#
+    ));
+
+    assert_eq!(actual, "6");
+}
+
+#[test]
+fn division_of_ints() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            = 4 / 2
+        "#
+    ));
+
+    assert_eq!(actual, "2");
+}
+
+#[test]
+fn division_of_ints2() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            = 1 / 4
+        "#
+    ));
+
+    assert_eq!(actual, "0.25");
+}
+
+#[test]
+fn parens_precedence() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            = 4 * (6 - 3)
+        "#
+    ));
+
+    assert_eq!(actual, "12");
+}
+
+#[test]
+fn compound_comparison() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            = 4 > 3 && 2 > 1
+        "#
+    ));
+
+    assert_eq!(actual, "true");
+}
+
+#[test]
+fn compound_comparison2() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            = 4 < 3 || 2 > 1
+        "#
+    ));
+
+    assert_eq!(actual, "true");
+}
+
+#[test]
+fn compound_where() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            echo '[{"a": 1, "b": 1}, {"a": 2, "b": 1}, {"a": 2, "b": 2}]' | from-json | where a == 2 && b == 1 | to-json
+        "#
+    ));
+
+    assert_eq!(actual, r#"{"a":2,"b":1}"#);
+}

crates/nu-cli/tests/commands/mod.rs

@@ -18,6 +18,7 @@ mod insert;
 mod last;
 mod lines;
 mod ls;
+mod math;
 mod mkdir;
 mod mv;
 mod open;