handle ParameterDescription message

src/Cmd.roc

@@ -16,7 +16,7 @@ module [
 ]
 
 import Protocol.Frontend exposing [FormatCode]
-import Protocol.Backend exposing [RowField]
+import Protocol.Backend exposing [RowField, ParameterField]
 import Pg.Result exposing [CmdResult]
 
 Cmd a err := Params { decode : CmdResult -> Result a err } []
@@ -35,14 +35,15 @@ Kind k : [
         {
             name : Str,
             fields : List RowField,
+            parameters : List ParameterField,
         },
 ]k
 
 fromSql : Str -> Cmd CmdResult []
 fromSql = \sql ->
     new (SqlCmd sql)
 
-prepared : { name : Str, fields : List RowField } -> Cmd CmdResult []
+prepared : { name : Str, fields : List RowField, parameters : List ParameterField } -> Cmd CmdResult []
 prepared = \prep ->
     new (PreparedCmd prep)
 
@@ -135,4 +136,3 @@ encodeSingle = \binding ->
                 value: Value (Str.toUtf8 value),
                 format: Text,
             }
-

src/Pg/BasicCliClient.roc

@@ -293,12 +293,16 @@ readCmdResult = \initFields, stream ->
     msg, state <- messageLoop stream {
             fields: initFields,
             rows: [],
+            parameters: [],
         }
 
     when msg is
-        ParseComplete | BindComplete | ParameterDescription | NoData ->
+        ParseComplete | BindComplete | NoData ->
             next state
 
+        ParameterDescription parameters ->
+            next { state & parameters: parameters }
+
         RowDescription fields ->
             next { state & fields: fields }
 
@@ -347,17 +351,20 @@ prepare = \sql, { name, client } ->
 
     Tcp.write! stream parseAndDescribe
 
-    msg, state <- messageLoop stream []
+    msg, state <- messageLoop stream { fields: [], parameters: [] }
 
     when msg is
-        ParseComplete | ParameterDescription | NoData ->
+        ParseComplete | NoData ->
             next state
 
+        ParameterDescription parameters ->
+            next { state & parameters: parameters }
+
         RowDescription fields ->
-            next fields
+            next { state & fields: fields }
 
         ReadyForQuery _ ->
-            return (Cmd.prepared { name, fields: state })
+            return (Cmd.prepared { name, fields: state.fields, parameters: state.parameters })
 
         _ ->
             unexpected msg

src/Pg/Result.roc

@@ -1,6 +1,7 @@
 module [
     CmdResult,
     RowField,
+    ParameterField,
     create,
     len,
     fields,
@@ -29,10 +30,12 @@ module [
 import Protocol.Backend
 
 RowField : Protocol.Backend.RowField
+ParameterField : Protocol.Backend.ParameterField
 
 CmdResult := {
     fields : List RowField,
     rows : List (List (List U8)),
+    parameters: List ParameterField,
 }
 
 create = @CmdResult

src/Protocol/Backend.roc

@@ -5,6 +5,7 @@ module [
     KeyData,
     Status,
     RowField,
+    ParameterField,
     Error,
 ]
 
@@ -34,7 +35,7 @@ Message : [
     BindComplete,
     NoData,
     RowDescription (List RowField),
-    ParameterDescription,
+    ParameterDescription (List ParameterField),
     DataRow (List (List U8)),
     PortalSuspended,
     CommandComplete Str,
@@ -80,7 +81,7 @@ message = \msgType ->
             rowDescription
 
         't' ->
-            succeed ParameterDescription
+            parameterDescription
 
         'D' ->
             dataRow
@@ -330,6 +331,28 @@ rowField =
         formatCode,
     }
 
+ParameterField : {
+    dataTypeOid : I32,
+}
+
+parameterDescription : Decode Message _
+parameterDescription =
+    fieldCount <- await i16
+
+    if fieldCount == 0 then
+        succeed (ParameterDescription [])
+    else
+        fixedList
+            fieldCount
+            parameterField
+        |> map ParameterDescription
+
+parameterField : Decode ParameterField _
+parameterField =
+    dataTypeOid <- await i32
+
+    succeed { dataTypeOid }
+
 dataRow : Decode Message _
 dataRow =
     columnCount <- await i16