Fixes pathing of expressions by visiting root.

Adds tests for pathing and scalar functions

partiql-lang/src/test/kotlin/org/partiql/lang/planner/transforms/PartiQLSchemaInferencerTests.kt

@@ -115,6 +115,16 @@ class PartiQLSchemaInferencerTests {
     @Execution(ExecutionMode.CONCURRENT)
     fun testAggregations(tc: TestCase) = runTest(tc)
 
+    @ParameterizedTest
+    @MethodSource("scalarFunctions")
+    @Execution(ExecutionMode.CONCURRENT)
+    fun testScalarFunctions(tc: TestCase) = runTest(tc)
+
+    @ParameterizedTest
+    @MethodSource("pathExpressions")
+    @Execution(ExecutionMode.CONCURRENT)
+    fun testPathExpressions(tc: TestCase) = runTest(tc)
+
     companion object {
 
         private val root = this::class.java.getResource("/catalogs/default")!!.toURI().toPath().pathString
@@ -2127,6 +2137,139 @@ class PartiQLSchemaInferencerTests {
             ),
         )
 
+        @JvmStatic
+        fun pathExpressions() = listOf(
+            SuccessTestCase(
+                name = "Index on literal list",
+                query = """
+                    [0, 1, 2, 3][0]
+                """,
+                expected = INT4
+            ),
+            SuccessTestCase(
+                name = "Index on global list",
+                query = """
+                    dogs[0].breed
+                """,
+                catalog = "pql",
+                catalogPath = listOf("main"),
+                expected = STRING
+            ),
+            SuccessTestCase(
+                name = "Index on list attribute of global table",
+                query = """
+                    SELECT typical_allergies[0] AS main_allergy FROM dogs
+                """,
+                catalog = "pql",
+                catalogPath = listOf("main"),
+                expected = BagType(
+                    StructType(
+                        fields = mapOf(
+                            "main_allergy" to STRING,
+                        ),
+                        contentClosed = true,
+                        constraints = setOf(
+                            TupleConstraint.Open(false),
+                            TupleConstraint.UniqueAttrs(true),
+                            TupleConstraint.Ordered
+                        )
+                    )
+                )
+            ),
+        )
+
+        @JvmStatic
+        fun scalarFunctions() = listOf(
+            SuccessTestCase(
+                name = "UPPER on binding tuple of literal string",
+                query = """
+                    SELECT
+                        UPPER(some_str) AS upper_str
+                    FROM
+                        << { 'some_str': 'hello world!' } >>
+                        AS t
+                """,
+                expected = BagType(
+                    StructType(
+                        fields = mapOf(
+                            "upper_str" to STRING,
+                        ),
+                        contentClosed = true,
+                        constraints = setOf(
+                            TupleConstraint.Open(false),
+                            TupleConstraint.UniqueAttrs(true),
+                            TupleConstraint.Ordered
+                        )
+                    )
+                )
+            ),
+            SuccessTestCase(
+                name = "UPPER on literal string",
+                query = """
+                    UPPER('hello world')
+                """,
+                expected = STRING
+            ),
+            SuccessTestCase(
+                name = "UPPER on global string",
+                query = """
+                    UPPER(os)
+                """,
+                catalog = "pql",
+                catalogPath = listOf("main"),
+                expected = STRING
+            ),
+            SuccessTestCase(
+                name = "UPPER on global string",
+                query = """
+                    UPPER(os)
+                """,
+                catalog = "pql",
+                catalogPath = listOf("main"),
+                expected = STRING
+            ),
+            SuccessTestCase(
+                name = "UPPER on global struct",
+                query = """
+                    UPPER(person.ssn)
+                """,
+                catalog = "pql",
+                catalogPath = listOf("main"),
+                expected = STRING
+            ),
+            SuccessTestCase(
+                name = "UPPER on global nested struct",
+                query = """
+                    UPPER(person.name."first")
+                """,
+                catalog = "pql",
+                catalogPath = listOf("main"),
+                expected = STRING
+            ),
+            SuccessTestCase(
+                name = "UPPER on global table",
+                query = """
+                    SELECT UPPER(breed) AS upper_breed
+                    FROM dogs
+                """,
+                catalog = "pql",
+                catalogPath = listOf("main"),
+                expected = BagType(
+                    StructType(
+                        fields = mapOf(
+                            "upper_breed" to STRING,
+                        ),
+                        contentClosed = true,
+                        constraints = setOf(
+                            TupleConstraint.Open(false),
+                            TupleConstraint.UniqueAttrs(true),
+                            TupleConstraint.Ordered
+                        )
+                    )
+                )
+            ),
+        )
+
         @JvmStatic
         fun aggregationCases() = listOf(
             SuccessTestCase(

partiql-planner/src/main/kotlin/org/partiql/planner/typer/PlanTyper.kt

@@ -453,8 +453,9 @@ internal class PlanTyper(
                     // rewrite root
                     rex(type, op) to steps
                 }
-                else -> node.root to node.steps
+                else -> visitRex(node.root, node.root.type) to node.steps
             }
+
             // short-circuit if whole path was matched
             if (steps.isEmpty()) {
                 return root

partiql-planner/src/testFixtures/resources/catalogs/default/pql/main/dogs.ion

@@ -0,0 +1,24 @@
+{
+  type: "list",
+  items: {
+    type: "struct",
+    constraints: [closed],
+    fields: [
+      {
+        name: "breed",
+        type: "string",
+      },
+      {
+        name: "avg_height",
+        type: "float32",
+      },
+      {
+        name: "typical_allergies",
+        type: {
+          type: "list",
+          items: "string"
+        }
+      }
+    ]
+  }
+}

partiql-planner/src/testFixtures/resources/catalogs/default/pql/main/os.ion

@@ -0,0 +1,2 @@
+// String representing the current operating system
+"string"