Stub let() yaml and convert tests to yaml

functions/let.yml

@@ -0,0 +1,50 @@
+examples:
+  with_filters:
+    context:
+      search_for: foo
+      people: [name: a, name: b, name: c, name: foo, name: bar, name: baz, name: qux,
+        name: x, name: y, name: z]
+    args: [{search_for: search_for}, '&people[?name==search_for].name | [0]']
+    returns: foo
+    comment: Let function with filters
+  basic1:
+    context: &data
+      a: {mylist: [{l1: '1', result: foo}, {l2: '2', result: bar}, {l1: '8', l2: '9'},
+          {l1: '8', l2: '9'}], level2: '2'}
+      level1: '1'
+      nested: {a: {b: {c: {fourth: fourth}, third: third}, second: second}, first: first}
+      precedence: {a: {b: {c: {variable: fourth}, variable: third, other: y}, variable: second,
+          other: x}, variable: first, other: w}
+    args: [{level1: level1}, '&a.[level2', 'level1]']
+    returns: ['2', '1']
+    comment: Basic let from scope
+  precedence:
+    context: *data
+    args: [{level1: "'other'"}, '&level1']
+    returns: '1'
+    comment: Current object has precedence
+  literal1:
+    context: *data
+    args: ['`{}`', '&a.level2']
+    returns: '2'
+    comment: No scope specified using literal hash
+  basic2:
+    context: *data
+    args: [{foo: "'anything'"}, '&[level1, foo]']
+    returns: ['1', anything]
+    comment: Arbitrary variable added
+  basic3:
+    context: *data
+    args: [{other: level1}, '&level1']
+    returns: '1'
+    comment: Basic let from current object
+  nested1:
+    context: *data
+    args: [{level1: level1}, '&a.[mylist[?l1==level1].result, let({level2: level2}, &mylist[?l2==level2].result)]']
+    returns: [foo, bar]
+    comment: Nested let function with filters
+  nested2:
+    context: *data
+    args: ['`{"level1": "1"}`', '&a.[mylist[?l1==level1].result, let({level2: level2}, &mylist[?l2==level2].result)]']
+    returns: [foo, bar]
+    comment: Nested let function with filters with literal scope binding

grammar/functions.yml

@@ -34,3 +34,20 @@ test4:
   query: foo[].not_null(f, e, d, c, b, a)
   returns: [b, c, d, e, f]
   comment: function projection on variadic function
+nested_let1:
+  context: &data
+    a: {mylist: [{l1: '1', result: foo}, {l2: '2', result: bar}, {l1: '8', l2: '9'},
+        {l1: '8', l2: '9'}], level2: '2'}
+    level1: '1'
+    nested: {a: {b: {c: {fourth: fourth}, third: third}, second: second}, first: first}
+    precedence: {a: {b: {c: {variable: fourth}, variable: third, other: y}, variable: second,
+        other: x}, variable: first, other: w}
+  comment: "Precedence of lexical vars from scope object"
+  query: "precedence.let({other: other}, &a.let({other: other}, &b.let({other: other}, &c.{other: other})))"
+  returns:
+    other: y
+nested_let2:
+  context: *data
+  comment: "Precedence of lexical vars from current object",
+  query: "precedence.let({variable: variable}, &a.let({variable: variable}, &b.let({variable: variable}, &c.let({variable: `\"override\"`}, &variable))))",
+  returns: "fourth"