partiql · johnedquinn · Aug 16, 2023
diff --git a/partiql-ast/src/main/resources/partiql_ast.ion b/partiql-ast/src/main/resources/partiql_ast.ion
@@ -114,6 +114,33 @@ statement::[
       definition: optional::table_definition,
     },
 
+    // CREATE FUNCTION
+    create_function::{
+      specification: specification,
+      body: routine_body,
+      _: [
+        specification::{
+          name: '.identifier.qualified',
+          parameters: list::[parameter_declaration],
+          returns: returns,
+          characteristics: list::[routine_characteristic],
+        },
+        parameter_declaration::{
+          name: optional::'.identifier.symbol',
+          type: '.type'
+        },
+        // SQL:1999
+        // <returns clause> ::= RETURNS <returns data type> [ <result cast> ]
+        // <returns data type> ::= <data type> [ <locator indication> ]
+        // <result cast> ::= CAST FROM <result cast from type>
+        // <result cast from type> ::= <data type> [ <locator indication> ]
+        // TODO: Eventually add other grammatical rules here
+        returns::{
+          type: '.type'
+        }
+      ]
+    },
+
     // CREATE INDEX [<identifier>] ON <identifier> (<path> [, <path>]...)
     create_index::{
       index:  optional::identifier,
@@ -133,6 +160,19 @@ statement::[
     },
   ],
 
+  // SQL:1999
+  // <SQL control statement> ::=
+  //     <call statement>
+  //     | <return statement>
+  // <return statement> ::=
+  //     RETURN <return value>
+  // <return value> ::=
+  //     <value expression>
+  //     | NULL
+  return::{
+    value: expr
+  },
+
   // EXEC <symbol> [<expr>.*]
   exec::{
     procedure: string,
@@ -149,6 +189,26 @@ statement::[
       },
     ],
   },
+
+  _::[
+    // SQL:1999
+    // <routine body> ::=
+    //     <SQL routine body>            <-- nicknaming this `internal`
+    //     | <external body reference>   <-- nicknaming this `external`
+    routine_body::[
+      // SQL:1999
+      // <SQL routine body> (nicknamed `internal`) ::= <SQL procedure statement>
+      // Note: Semantic pass should ensure the statement is a procedure statement.
+      internal::{
+        procedure_statement: statement
+      }
+    ],
+    routine_characteristic::[
+      specific::{
+        name: '.identifier.qualified'
+      }
+    ]
+  ]
 ]
 
 // PartiQL Type AST nodes

diff --git a/partiql-parser/src/main/antlr/PartiQL.g4 b/partiql-parser/src/main/antlr/PartiQL.g4
@@ -19,8 +19,153 @@ statement
     | dml COLON_SEMI? EOF          # QueryDml
     | ddl COLON_SEMI? EOF          # QueryDdl
     | execCommand COLON_SEMI? EOF  # QueryExec
+    | sqlInvokedRoutine            # CreateRoutineStatement
     ;
 
+// SQL:1999
+// <SQL-invoked routine> ::= <schema routine>
+sqlInvokedRoutine
+    : schemaRoutine
+    ;
+
+// SQL:1999
+// <schema routine> ::=
+//     <schema procedure>
+//     | <schema function>
+schemaRoutine
+    : schemaFunction
+    ;
+
+// SQL:1999
+// <schema function> ::=
+//     CREATE <SQL-invoked function>
+schemaFunction
+    : CREATE sqlInvokedFunction
+    ;
+
+// SQL:1999
+// <SQL-invoked function> ::=
+//     { <function specification> | <method specification designator> }
+//     <routine body>
+sqlInvokedFunction
+    :
+        (
+            functionSpecification
+        ) routineBody
+    ;
+
+// SQL:1999
+// <function specification> ::=
+//    FUNCTION <schema qualified routine name>
+//        <SQL parameter declaration list>
+//        <returns clause>
+//        <routine characteristics>
+//        [ <dispatch clause> ]
+functionSpecification
+    : FUNCTION name=symbolPrimitive // FIXME: Should be schemaQualifiedRoutineName
+        sqlParameterDeclarationList
+        returnsClause
+        routineCharacteristic*
+    ;
+
+// SQL:1999
+// <routine characteristic> ::=
+//     SPECIFIC <specific name>
+//     | and many more...
+routineCharacteristic
+    : SPECIFIC specificName
+    ;
+
+// SQL:1999
+// <specific name> ::= <schema qualified name>
+specificName
+    : name=symbolPrimitive // FIXME: should be ```schemaQualifiedName```
+    ;
+
+// SQL:1999
+// <returns clause> ::= RETURNS <returns data type> [ <result cast> ]
+returnsClause
+    : RETURNS returnsDataType
+    ;
+
+// SQL:1999
+// <returns data type> ::= <data type> [ <locator indication> ]
+returnsDataType
+    : type
+    ;
+
+// SQL:1999
+// <routine body> ::=
+//     <SQL routine body>
+//     | <external body reference>
+routineBody
+    : sqlRoutineBody
+    ;
+
+// SQL:1999
+// <SQL parameter declaration list> ::=
+//     <left paren>
+//     [ <SQL parameter declaration> [ { <comma> <SQL parameter declaration> }... ] ]
+//     <right paren>
+sqlParameterDeclarationList
+    : PAREN_LEFT (sqlParameterDeclaration (COMMA sqlParameterDeclaration)* )? PAREN_RIGHT
+    ;
+
+// SQL:1999
+// <SQL parameter declaration> ::=
+//     [ <parameter mode> ] [ <SQL parameter name> ]
+//     <parameter type>
+//     [ RESULT ]
+sqlParameterDeclaration
+    : sqlParameterName? parameterType
+    ;
+
+// SQL:1999
+// <SQL parameter name> ::= <identifier>
+sqlParameterName
+    : symbolPrimitive
+    ;
+
+// SQL:1999
+// <parameter type> ::=
+//     <data type> [ <locator indication> ]
+parameterType
+    : type
+    ;
+
+// SQL:1999
+// <SQL routine body> ::= <SQL procedure statement>
+sqlRoutineBody: sqlProcedureStatement;
+
+// SQL:1999
+// <SQL procedure statement> ::= <SQL executable statement>
+sqlProcedureStatement: sqlExecutableStatement;
+
+// SQL:1999
+// <SQL executable statement> ::=
+//     <SQL control statement>
+//     | many more alternatives...
+sqlExecutableStatement
+    : sqlControlStatement
+    ;
+
+// SQL:1999
+// <SQL control statement> ::=
+//     <call statement>
+//     | <return statement>
+sqlControlStatement
+    : returnStatement
+    ;
+
+// SQL:1999
+// <return statement> ::=
+//     RETURN <return value>
+// <return value> ::=
+//     <value expression>
+//     | NULL
+returnStatement
+    : RETURN expr;
+
 /**
  *
  * COMMON STRUCTURES

diff --git a/partiql-parser/src/main/antlr/PartiQLTokens.g4 b/partiql-parser/src/main/antlr/PartiQLTokens.g4
@@ -119,6 +119,7 @@ FOREIGN: 'FOREIGN';
 FOUND: 'FOUND';
 FROM: 'FROM';
 FULL: 'FULL';
+FUNCTION: 'FUNCTION';
 GET: 'GET';
 GLOBAL: 'GLOBAL';
 GO: 'GO';
@@ -197,6 +198,8 @@ REFERENCES: 'REFERENCES';
 RELATIVE: 'RELATIVE';
 REPLACE: 'REPLACE';
 RESTRICT: 'RESTRICT';
+RETURN: 'RETURN';
+RETURNS: 'RETURNS';
 REVOKE: 'REVOKE';
 RIGHT: 'RIGHT';
 ROLLBACK: 'ROLLBACK';
@@ -213,6 +216,7 @@ SIZE: 'SIZE';
 SMALLINT: 'SMALLINT';
 SOME: 'SOME';
 SPACE: 'SPACE';
+SPECIFIC: 'SPECIFIC';
 SQL: 'SQL';
 SQLCODE: 'SQLCODE';
 SQLERROR: 'SQLERROR';

diff --git a/partiql-parser/src/main/kotlin/org/partiql/parser/impl/PartiQLParserDefault.kt b/partiql-parser/src/main/kotlin/org/partiql/parser/impl/PartiQLParserDefault.kt
@@ -508,6 +508,82 @@ internal class PartiQLParserDefault : PartiQLParser {
             statementExec(procedure, args)
         }
 
+        // FUNCTION
+
+        override fun visitSqlInvokedRoutine(ctx: org.partiql.parser.antlr.PartiQLParser.SqlInvokedRoutineContext?): AstNode {
+            return super.visitSqlInvokedRoutine(ctx)
+        }
+
+        override fun visitSchemaRoutine(ctx: org.partiql.parser.antlr.PartiQLParser.SchemaRoutineContext?): AstNode {
+            return super.visitSchemaRoutine(ctx)
+        }
+
+        override fun visitSchemaFunction(ctx: org.partiql.parser.antlr.PartiQLParser.SchemaFunctionContext?): AstNode {
+            return super.visitSchemaFunction(ctx)
+        }
+
+        override fun visitSqlInvokedFunction(ctx: org.partiql.parser.antlr.PartiQLParser.SqlInvokedFunctionContext) = translate(ctx) {
+            val specification = visitFunctionSpecification(ctx.functionSpecification())
+            val body = visitRoutineBody(ctx.routineBody())
+            statementDDLCreateFunction(specification, body)
+        }
+
+        override fun visitFunctionSpecification(ctx: org.partiql.parser.antlr.PartiQLParser.FunctionSpecificationContext) = translate(ctx) {
+            val root = visitSymbolPrimitive(ctx.name)
+            val name = identifierQualified(root, emptyList())
+            val parameters = ctx.sqlParameterDeclarationList().sqlParameterDeclaration().map { decl ->
+                visitSqlParameterDeclaration(decl)
+            }
+            val returns = visitReturnsClause(ctx.returnsClause())
+            val characteristics = ctx.routineCharacteristic().map { characteristic ->
+                visitRoutineCharacteristic(characteristic)
+            }
+            statementDDLCreateFunctionSpecification(name, parameters, returns, characteristics)
+        }
+
+        override fun visitSqlParameterDeclaration(ctx: org.partiql.parser.antlr.PartiQLParser.SqlParameterDeclarationContext) = translate(ctx) {
+            val name = ctx.sqlParameterName()?.let { visitSymbolPrimitive(it.symbolPrimitive()) }
+            val type = visit(ctx.parameterType().type()) as Type
+            statementDDLCreateFunctionParameterDeclaration(name, type)
+        }
+
+        override fun visitReturnsClause(ctx: org.partiql.parser.antlr.PartiQLParser.ReturnsClauseContext) = translate(ctx) {
+            val type = visit(ctx.returnsDataType().type()) as Type
+            statementDDLCreateFunctionReturns(type)
+        }
+
+        override fun visitRoutineCharacteristic(ctx: org.partiql.parser.antlr.PartiQLParser.RoutineCharacteristicContext) = translate(ctx) {
+            val name = visitSymbolPrimitive(ctx.specificName().name)
+            val specificName = identifierQualified(name, emptyList())
+            statementRoutineCharacteristicSpecific(specificName)
+        }
+
+        override fun visitReturnStatement(ctx: org.partiql.parser.antlr.PartiQLParser.ReturnStatementContext) = translate(ctx) {
+            val expr = visitExpr(ctx.expr())
+            statementReturn(expr)
+        }
+
+        override fun visitSqlProcedureStatement(ctx: org.partiql.parser.antlr.PartiQLParser.SqlProcedureStatementContext?): AstNode {
+            return super.visitSqlProcedureStatement(ctx)
+        }
+
+        override fun visitSqlExecutableStatement(ctx: org.partiql.parser.antlr.PartiQLParser.SqlExecutableStatementContext?): AstNode {
+            return super.visitSqlExecutableStatement(ctx)
+        }
+
+        override fun visitRoutineBody(ctx: org.partiql.parser.antlr.PartiQLParser.RoutineBodyContext) = translate(ctx) {
+            visitSqlRoutineBody(ctx.sqlRoutineBody())
+        }
+
+        override fun visitSqlRoutineBody(ctx: org.partiql.parser.antlr.PartiQLParser.SqlRoutineBodyContext) = translate(ctx) {
+            val stmt = visitSqlProcedureStatement(ctx.sqlProcedureStatement()) as Statement
+            statementRoutineBodyInternal(stmt)
+        }
+
+        override fun visitSqlControlStatement(ctx: org.partiql.parser.antlr.PartiQLParser.SqlControlStatementContext?): AstNode {
+            return super.visitSqlControlStatement(ctx)
+        }
+
         /**
          *
          * DATA MANIPULATION LANGUAGE (DML)
@@ -1835,6 +1911,7 @@ internal class PartiQLParserDefault : PartiQLParser {
             val n = ctx.arg0?.text?.toInt()
             when (ctx.datatype.type) {
                 GeneratedParser.FLOAT -> when (n) {
+                    null -> typeFloat64()
                     32 -> typeFloat32()
                     64 -> typeFloat64()
                     else -> throw error(ctx.datatype, "Invalid FLOAT precision. Expected 32 or 64")