alguidelines.dev - Business Central Design Patterns – Best Practice

Docs: 3. CAL Coding Guidelines

Mon, 01 Jan 0001 00:00:00 +0000

We’ve decided to publish our current C/AL coding guidelines. They are actual, as per January 2015 when this is published (but might fall out of sync as time goes by).

You can also download the C/AL coding guidelines as pdf, all in one document. In contrast, on this wiki, the coding guidelines are published individually. The reason is: give you the chance to comment and share your oppinion on each one. Thanks to waldo for this idea and for helping out.

The guidelines are debatable - and it is good when they are generating debate. There is variation of opinion on the rules at Microsoft too. The plan is to simply expose what we use now. And more important, to say that guidelines could be used. Debate on individual guidelines can become heated for any programming language, but the benefit of using some guidelines stays.

For us, those guidelines are enforced at check-in time - we are using a tool which verifies and only allows compliant check-ins. While this tool is internal and not ready to publish, we had anyways decided to open up and present the rules we use to the community, as inspiration.

Question: Since we’re having the guidelines, how come there is still C/AL code in NAV which doesn’t respect them?

Answer: all new C/AL code is bound to follow the guidelines (else it cannot be checked-in). However, the code that existed before the rules - it does not. We had done cleanup in a certain degree. Now we’re gradually improving the old code base as we visit various objects in order to add new functionality, however chances are that code we didn’t touch in a long time had remained in its old form.

We’re looking forward to your comments. Where you can, do provide concrete examples of the alternatives, Good and Bad.

Docs: Actions - Images

Mon, 01 Jan 0001 00:00:00 +0000

All actions must have an image assigned to them.

Bad code

{ 7 ;1 ;Action ;
 CaptionML=ENU=Customer - &Balance;
 RunObject=Report 121 }

Good code

{ 7 ;1 ;Action ;
 CaptionML=ENU=Customer - &Balance;
 RunObject=Report 121 }
 Image=Report }

Docs: Begin as an 'After Word'

Mon, 01 Jan 0001 00:00:00 +0000

When BEGIN follows THEN, ELSE, DO, it should be on the same line, preceded by one space character.

Bad code

IF ICPartnerRefType = ICPartnerRefType::"Common Item No." THEN
 BEGIN
 ...
END;

Good code

IF ICPartnerRefType = ICPartnerRefType::"Common Item No." THEN BEGIN
...
END;

Docs: Begin-End - Compound Only

Mon, 01 Jan 0001 00:00:00 +0000

Only use BEGIN..END to enclose compound statements.

Bad code

IF FINDSET THEN BEGIN
 REPEAT
 ...
 UNTIL NEXT = 0;
END;

Good code

IF FINDSET THEN
 REPEAT
 ...
 UNTIL NEXT = 0;

Bad code

IF IsAssemblyOutputLine THEN BEGIN
 TESTFIELD("Order Line No.",0);
END;

Good code

IF IsAssemblyOutputLine THEN
 TESTFIELD("Order Line No.",0);

Bad code

IF FINDSET THEN
 REPEAT
 BEGIN
 ...
 END;
 UNTIL NEXT = 0;

Good code

IF FINDSET THEN
 REPEAT
 ...
 UNTIL NEXT = 0;

Exception

// Except for this case
IF X THEN BEGIN
 IF Y THEN
 DO SOMETHING;
END ELSE (not X)

Docs: Binary Operator to Start Line

Mon, 01 Jan 0001 00:00:00 +0000

Do not start a line with a binary operator.

Bad code

"Quantity to Ship" :=
 Quantity
 - "Quantity Shipped"

Good code

"Quantity to Ship" :=
 Quantity -
 "Quantity Shipped"

Docs: Blank Lines

Mon, 01 Jan 0001 00:00:00 +0000

Do not use blank lines at the beginning or end of any functions, after BEGIN, before END, or inside multiline expressions.

Bad code

PROCEDURE MATRIX_OnDrillDown@1133(MATRIX_ColumnOrdinal : Integer);
BEGIN

 SetupDrillDownCol(MATRIX_ColumnOrdinal);
 DrillDown(FALSE,ValueType);

END;

Good code

PROCEDURE MATRIX_OnDrillDown@1133(MATRIX_ColumnOrdinal : Integer);
BEGIN
 SetupDrillDownCol(MATRIX_ColumnOrdinal);
 DrillDown(FALSE,ValueType);
END;

Bad code

IF NameIsValid AND

 Name2IsValid
THEN

Good code

IF NameIsValid AND
 Name2IsValid
THEN

Docs: By Reference Parameters

Mon, 01 Jan 0001 00:00:00 +0000

Do not declare parameters by reference if their values are not intended to be changed.

Unintentional value changes might propagate. Also, it might lead people to believe that value changes are intended.

Bad code

LOCAL PROCEDURE ShowMessage@15(VAR Text@1000 : Text[250]);
BEGIN
Text := GetMessageText;
IF (Text <> '') AND GenJnlLineInserted THEN
MESSAGE(Text);
END;

Good code

LOCAL PROCEDURE ShowMessage@15(Text@1000 : Text[250]);
BEGIN
Text := GetMessageText;
IF (Text <> '') AND GenJnlLineInserted THEN
MESSAGE(Text);
END;

Docs: CaptionML on System Pages

Mon, 01 Jan 0001 00:00:00 +0000

CaptionML should always be specified on a page field for a system table. By default, system tables do not have captions, so if you need to use them in the UI then captions need to be added.

Bad code

...
{ 2 ;2 ;Field ;
SourceExpr=Name }
...
OBJECT Table 2000000000 User
...
{ 2 ; ;Name ;Text50 }

Good code

...
{ 2 ;2 ;Field ;
CaptionML=ENU=Name;
SourceExpr=Name }
...
OBJECT Table 2000000000 User
...
{ 2 ; ;Name ;Text50 }

Docs: CASE Action

Mon, 01 Jan 0001 00:00:00 +0000

A CASE action should start on a line after the possibility.

Bad code

CASE Letter OF
 'A': Letter2 := '10';
 'B': Letter2 := '11';

Good code

CASE Letter OF
 'A':
 Letter2 := '10';
 'B':
 Letter2 := '11';

Docs: Class Coupling

Mon, 01 Jan 0001 00:00:00 +0000

Do not write functions that have high class coupling. This makes the code hard to maintain.

Bad code

Any procedure / trigger that has class coupling of > 30

Good code

Any procedure / trigger that has class coupling of <= 30\.
Class coupling is computed by summing the unique instances of the following in a code block:
- every unique usage of a complex C/AL data type (table, codeunit, etc) as 1\.
- every unique usage of a DotNet type as 1\.

Docs: Colon usage in CASE

Mon, 01 Jan 0001 00:00:00 +0000

The last possibility on a CASE statement must be immediately followed by a colon.

Bad code

CASE DimOption OF
 DimOption::"Global Dimension 1" :
 DimValue."Dimension Code" := GLSetup."Global Dimension 1 Code";

Good code

CASE DimOption OF
 DimOption::"Global Dimension 1":
 DimValue."Dimension Code" := GLSetup."Global Dimension 1 Code";

Docs: Comments inside Curly Brackets

Mon, 01 Jan 0001 00:00:00 +0000

Never use curly bracket comments. During development, the “Block comment” functionality can be used instead. However, in production code, block comments are not recommended.

Bad code

PeriodTxt: {Period}

Good code

PeriodTxt: // Period

Bad code

PROCEDURE MATRIX_OnAfterGetRecord@10(MATRIX_ColumnOrdinal : Integer);
BEGIN
 {
 IF ShowColumnName THEN
 MatrixHeader := MatrixRecords[MATRIX_ColumnOrdinal].Name
 ELSE
 MatrixHeader := MatrixRecords[MATRIX_ColumnOrdinal].Code;
 }
 MatrixRecord := MatrixRecords[MATRIX_ColumnOrdinal];
 AnalysisValue := CalcAmt(ValueType,TRUE);
 MATRIX_CellData[MATRIX_ColumnOrdinal] := AnalysisValue;
END;

Good code

PROCEDURE MATRIX_OnAfterGetRecord@10(MATRIX_ColumnOrdinal : Integer);
BEGIN
 MatrixRecord := MatrixRecords[MATRIX_ColumnOrdinal];
 AnalysisValue := CalcAmt(ValueType,TRUE);
 MATRIX_CellData[MATRIX_ColumnOrdinal] := AnalysisValue;
END;

Docs: Comment Spacing

Mon, 01 Jan 0001 00:00:00 +0000

Always start comments with // followed by one space character.

Bad code

RowNo += 1000; //Move way below the budget

Good code

RowNo += 1000; // Move way below the budget

Docs: CONFIRM

Mon, 01 Jan 0001 00:00:00 +0000

Always end CONFIRM with a question mark.

Bad code

ChangeAllOpenedEntriesQst@1000 : TextConst 'ENU=Do you want to change all open entries for every customer and vendor that are not blocked';
...
IF CONFIRM(ChangeAllOpenedEntriesQst,TRUE) THEN

Good code

ChangeAllOpenedEntriesQst@1000 : TextConst 'ENU=Do you want to change all open entries for every customer and vendor that are not blocked?';
...
IF CONFIRM(ChangeAllOpenedEntriesQst,TRUE) THEN

Docs: Cyclomatic Complexity

Mon, 01 Jan 0001 00:00:00 +0000

Do not write functions that have high cyclomatic complexity. This makes the code hard to maintain.

Bad code

Any procedure / trigger that has a cyclomatic complexity > 25, using the CC3 version mentioned in [this article][anchor0].

Good code

Any procedure / trigger that has a cyclomatic complexity <= 25, using the CC3 version.
The CC3 version is computed by summing the following in a code block:
- each IF statement as 1\.
- each entire CASE as 1\.

Docs: Design

Mon, 01 Jan 0001 00:00:00 +0000

C/AL Coding Guidelines

Design

Find the C/AL guidelines by expanding the menu in the left.

Docs: Encapsulate Local Functionality

Mon, 01 Jan 0001 00:00:00 +0000

Any function used local must be defined as local.

Docs: END ELSE Pair

Mon, 01 Jan 0001 00:00:00 +0000

The END ELSE pair should always appear on the same line.

Bad code

IF OppEntry.FIND('-') THEN
 IF SalesCycleStage.FIND('-') THEN BEGIN
 ...
 END
ELSE
 ...

Good code

IF OppEntry.FIND('-') THEN
 IF SalesCycleStage.FIND('-') THEN BEGIN
 ...
END ELSE
 ...

Docs: FIELDCAPTION and TABLECAPTION

Mon, 01 Jan 0001 00:00:00 +0000

For user messages, errors etc., use FIELDCAPTION not FIELDNAME and TABLECAPTION not TABLENAME.

Reason:

The correct translation will be automatically used.
If the caption/name changes, then there will be a single point of change needed.

Bad code

IF NOT CONFIRM(UpdateLocationQst,TRUE,FIELDNAME("Location Code"),...)

Good code

IF NOT CONFIRM(UpdateLocationQst,TRUE,FIELDCAPTION("Location Code"),...)

Docs: FIELDERROR

Mon, 01 Jan 0001 00:00:00 +0000

Never use FIELDERROR with a period as it is automatically inserted.

Bad code

InvalidValue@1025 : TextConst 'ENU=is invalid.';
...
Cust.FIELDERROR("No.",InvalidValue);

Good code

InvalidValue@1025 : TextConst 'ENU=is invalid';
...
Cust.FIELDERROR("No.",InvalidValue);

Docs: FINDSET FINDFIRST FINDLAST

Mon, 01 Jan 0001 00:00:00 +0000

FINDSET, FIND(’+’) or FIND(’-’) should only be used when NEXT is used and vice versa.

Bad code

IF Cust.FIND('-') THEN
ERROR(CustIsBlockErr)

Good code

IF Cust.FINDFIRST THEN
ERROR(CustIsBlockErr)

Bad code

IF Cust.FINDFIRST THEN
REPEAT
...
UNTIL Cust.NEXT = 0;

Good code

IF Cust.FINDSET THEN
REPEAT
...
UNTIL Cust.NEXT = 0;

Docs: Global Text Constants

Mon, 01 Jan 0001 00:00:00 +0000

Declare Text Constant as global variables.

Bad code

PROCEDURE GetRequirementText@6(...) : Text[50];
VAR
 RequirementOptionsTxt@1002 : TextConst 'ENU=Shipment,Receive,Pick,Put-Away';
BEGIN

Good code

VAR
 RequirementOptionsTxt@1002 : TextConst 'ENU=Shipment,Receive,Pick,Put-Away';
...
PROCEDURE GetRequirementText@6(...) : Text[50];
BEGIN

Docs: Indentation

Mon, 01 Jan 0001 00:00:00 +0000

In general, use an indentation of two space characters. Logical expressions in the IF, WHILE, and UNTIL parts are indented at least 3, 6, and 6 spaces respectively.

Bad code

IF GLSetup."Unrealized VAT" OR
 (GLSetup."Prepayment Unrealized VAT" AND NewCVLedgEntryBuf.Prepayment)

Good code

IF GLSetup."Unrealized VAT" OR
 (GLSetup."Prepayment Unrealized VAT" AND NewCVLedgEntryBuf.Prepayment)

Bad code

IF GenJnlLine."Account No." <> ICPartner.Code THEN
 ICPartner.GET("Account No.");
 IF GenJnlLine.Amount \> 0 THEN BEGIN
 ...

Good code

IF GenJnlLine."Account No." <> ICPartner.Code THEN
 ICPartner.GET("Account No.");
IF GenJnlLine.Amount > 0 THEN BEGIN
 ...

Bad code

Dialog.OPEN(WindowTxt +
 '@1@@@@@@@@@@@@@@@@@@@@@@@');

Good code

Dialog.OPEN(
 WindowTxt +
 '@1@@@@@@@@@@@@@@@@@@@@@@@');

Bad code

TempOldCustLedgEntry.DELETE;
 // Find the next old entry for application of the new entry

Good code

TempOldCustLedgEntry.DELETE;
// Find the next old entry for application of the new entry

Bad code

IF NOT ("Applies-to Doc. Type" IN
 ["Applies-to Doc. Type"::Receipt,
 "Applies-to Doc. Type"::"Return Shipment"])

Good code

IF NOT ("Applies-to Doc. Type" IN
 ["Applies-to Doc. Type"::Receipt,
 "Applies-to Doc. Type"::"Return Shipment"])

Bad code

WHILE (RemAmt > 0) OR
 (RemAmtLCY > 0)
DO

Good code

WHILE (RemAmt > 0) OR
 (RemAmtLCY > 0)
DO

Bad code

UNTIL (RemAmt > 0) AND
 (RemAmtLCY > 0);

Good code

UNTIL (RemAmt > 0) AND
 (RemAmtLCY > 0)

Docs: Initialized Variables

Mon, 01 Jan 0001 00:00:00 +0000

Variables should always be set to a specific value, before they are used.

Bad code

PROCEDURE SetPurchLine@22(VAR CurrentPurchLine@1000 : Record 39);
VAR
Pegging@1001 : Boolean;
BEGIN
IF Pegging THEN
CurrQuantity := CurrentPurchLine."Quantity (Base)"
ELSE
CurrQuantity := CurrentPurchLine."Outstanding Qty. (Base)";
END;

Good code

PROCEDURE SetPurchLine@22(VAR CurrentPurchLine@1000 : Record 39);
VAR
Pegging@1001 : Boolean;
BEGIN
Pegging := IsPegging(CurrentPurchLine);
IF Pegging THEN
CurrQuantity := CurrentPurchLine."Quantity (Base)"
ELSE
CurrQuantity := CurrentPurchLine."Outstanding Qty. (Base)";
END;

Bad code

// In the example below, the function will always return FALSE.
PROCEDURE GetItemsToPlan@22() : Boolean;
BEGIN
SETRANGE("Document Type","Document Type"::Order);
...
FINDSET
END;

Good code

PROCEDURE GetItemsToPlan@22() : Boolean;
BEGIN
SETRANGE("Document Type","Document Type"::Order);
...
EXIT(FINDSET)
END;

Docs: Internally used DotNet Types

Mon, 01 Jan 0001 00:00:00 +0000

(Dynamics NAV 2015)

Dot Net Types

‘mscorlib’.System.Convert

‘mscorlib’.System.Globalization.CultureInfo

‘mscorlib’.System.Globalization.DateTimeStyles

‘mscorlib’.System.Globalization.NumberStyles

‘mscorlib’.System.Type

‘mscorlib’.System.Array

‘mscorlib’.System.EventArgs

‘mscorlib’.System.Security.Cryptography.SHA512Managed

‘mscorlib’.System.Security.Cryptography.HashAlgorithm

‘mscorlib’.System.Text.Encoding

‘mscorlib’.System.Text.UTF8Encoding

‘mscorlib’.System.Environment

‘mscorlib’.System.IO.Directory

‘mscorlib’.System.IO.Path

‘mscorlib’.System.IO.File

‘mscorlib’.System.IO.FileAttributes

‘mscorlib’.System.Collections.ArrayList

‘mscorlib’.System.Collections.IEnumerator

‘mscorlib’.System.Collections.Generic.IEnumerator`1

‘mscorlib’.System.TimeSpan

‘mscorlib’.System.DateTime

‘mscorlib’.System.DateTimeKind

‘mscorlib’.System.DateTimeOffset

‘mscorlib’.System.Decimal

‘mscorlib’.System.String

‘System’.System.Diagnostics.Process

‘System’.System.Diagnostics.ProcessStartInfo

‘System’.System.IO.Compression.CompressionMode

‘System’.System.IO.Compression.GZipStream

‘System’.System.Uri

‘System’.System.UriPartial

‘System.Data’.System.Data.DataColumn

‘System.Data’.System.Data.DataTable

‘System.Data’.System.Data.DataRow

‘System.Web’.System.Web.HttpUtility

‘System.Windows.Forms’.System.Windows.Forms.DialogResult

‘System.Windows.Forms’.System.Windows.Forms.FileDialog

‘System.Windows.Forms’.System.Windows.Forms.OpenFileDialog

‘System.Windows.Forms’.System.Windows.Forms.SaveFileDialog

‘System.Windows.Forms’.System.Windows.Forms.FolderBrowserDialog

‘System.Xml’.*

‘DocumentFormat.OpenXml’.*

‘mscorlib’.System.IO.DirectoryInfo

‘mscorlib’.System.IO.FileInfo

‘Microsoft.Dynamics.Nav.Client.CodeViewerTypes’.Microsoft.Dynamics.Nav.Client.CodeViewerTypes.BreakpointCollection

‘Microsoft.Dynamics.Nav.Client.CodeViewerTypes’.Microsoft.Dynamics.Nav.Client.CodeViewerTypes.VariableCollection

‘Microsoft.Dynamics.Nav.SMTP’.Microsoft.Dynamics.Nav.SMTP.SmtpMessage

‘Microsoft.Dynamics.Nav.Management.DSObjectPickerWrapper’.*

‘Microsoft.Dynamics.Nav.Timer’.*

‘Microsoft.Dynamics.Nav.DO.ClientProxyWrapper’.*

‘Microsoft.Dynamics.Nav.Client.BusinessChart’.*

‘Microsoft.Dynamics.Nav.Client.BusinessChart.Model’.*

‘Microsoft.Dynamics.Nav.Integration.Office’.*

‘Microsoft.Dynamics.Nav.Integration.Office.Mock’.*

‘Microsoft.Dynamics.Nav.EwsWrapper’.*

‘Microsoft.Dynamics.Nav.EwsWrapper.ALTestHelper’.*

‘Microsoft.Dynamics.NAV.OLSync.OLSyncSupplier’.*

‘Microsoft.Dynamics.Nav.OLSync.Common’.*

‘Microsoft.Dynamics.Nav.NavUserAccount’.*

‘Microsoft.Dynamics.Nav.OpenXml’.*

‘Microsoft.Dynamics.Nav.RapidStart’.*

‘Microsoft.Dynamics.Framework.RapidStart.Common’.*

‘Microsoft.Dynamics.Nav.Client.TimelineVisualization’.Microsoft.Dynamics.Nav.Client.TimelineVisualization.

VisualizationScenarios

‘Microsoft.Dynamics.Framework.UI.WinForms.DataVisualization.Timeline’.Microsoft.Dynamics.Framework.UI.

WinForms.DataVisualization.TimelineVisualization.DataModel+TransactionChangesRow

‘Microsoft.Dynamics.Framework.UI.WinForms.DataVisualization.Timeline’.Microsoft.Dynamics.Framework.UI.

WinForms.DataVisualization.TimelineVisualization.DataModel+TransactionChangesDataTable

‘Microsoft.Dynamics.Framework.UI.WinForms.DataVisualization.Timeline’.Microsoft.Dynamics.Framework.UI.

WinForms.DataVisualization.TimelineVisualization.DataModel+TransactionRow

‘Microsoft.Dynamics.Framework.UI.WinForms.DataVisualization.Timeline’.Microsoft.Dynamics.Framework.UI.

WinForms.DataVisualization.TimelineVisualization.DataModel+TransactionDataTable

‘Microsoft.Office.Interop.Word’.*

‘Microsoft.Office.Interop.Excel’.*

‘Microsoft.Dynamics.BAPIWrapper’.*

‘Microsoft.Dynamics.Nav.Types’.Microsoft.Dynamics.Nav.Types.ConfigSettings

‘Microsoft.Dynamics.Nav.DocumentService’.*

‘Microsoft.Dynamics.Nav.DocumentService.Types’.*

‘mscorlib’.System.IO.StreamWriter

‘Microsoft.Dynamics.Nav.Client.TimelineVisualization’.Microsoft.Dynamics.Nav.Client.TimelineVisualization.

InteractiveTimelineVisualizationAddIn

‘System’.System.ComponentModel.CancelEventArgs

‘System’.System.Text.RegularExpressions.Regex

‘System’.System.Text.RegularExpressions.RegexOptions

‘mscorlib’.System.IO.StreamReader

‘System.Windows.Forms’.System.Windows.Forms.Control

‘System.Windows.Forms’.System.Windows.Forms.ControlEventArgs

‘System.Windows.Forms’.System.Windows.Forms.DragEventArgs

‘System.Windows.Forms’.System.Windows.Forms.GiveFeedbackEventArgs

‘System.Windows.Forms’.System.Windows.Forms.HelpEventArgs

‘System.Windows.Forms’.System.Windows.Forms.InvalidateEventArgs

‘System.Windows.Forms’.System.Windows.Forms.KeyEventArgs

‘System.Windows.Forms’.System.Windows.Forms.KeyPressEventArgs

‘System.Windows.Forms’.System.Windows.Forms.LayoutEventArgs

‘System.Windows.Forms’.System.Windows.Forms.MouseEventArgs

‘System.Windows.Forms’.System.Windows.Forms.PaintEventArgs

‘System.Windows.Forms’.System.Windows.Forms.PreviewKeyDownEventArgs

‘System.Windows.Forms’.System.Windows.Forms.QueryAccessibilityHelpEventArgs

‘System.Windows.Forms’.System.Windows.Forms.UICuesEventArgs

Docs: Internationalization

Mon, 01 Jan 0001 00:00:00 +0000

C/AL Coding Guidelines

Internationalization

Find the C/AL guidelines by expanding the menu in the left.

Docs: Keyword Pairs - Indentation

Mon, 01 Jan 0001 00:00:00 +0000

The IF..THEN pair, WHILE..DO pair, and FOR..DO pair must appear on the same line or the same level of indentation.

Bad code

IF (x = y) AND
 (a = b) THEN

Good code

IF (x = y) AND
 (a = b)
THEN

Docs: Line Start Keywords

Mon, 01 Jan 0001 00:00:00 +0000

The END, IF, REPEAT, FOR, WHILE, ELSE and CASE statement should always start a line.

Bad code

IF IsContactName THEN ValidateContactName
 ELSE IF IsSalespersonCode THEN ValidateSalespersonCode
 ELSE IF IsSalesCycleCode THEN ValidatSalesCycleCode;

Good code

IF IsContactName THEN
 ValidateContactName
ELSE
 IF IsSalespersonCode THEN
 ValidateSalespersonCode
 ELSE
 IF IsSalesCycleCode THEN
 ValidatSalesCycleCode;

Docs: Localizability

Mon, 01 Jan 0001 00:00:00 +0000

C/AL Coding Guidelines

Localizability

Find the C/AL guidelines by expanding the menu in the left.

Docs: Lonely Repeat

Mon, 01 Jan 0001 00:00:00 +0000

The REPEAT statement should always be alone on a line.

Bad code

IF ReservEntry.FINDSET THEN REPEAT

Good code

IF ReservEntry.FINDSET THEN
 REPEAT

Docs: Maintainability Index

Mon, 01 Jan 0001 00:00:00 +0000

Maintainability Index: Do not write functions that have a very low maintainability index. This makes the code hard to maintain.

Bad code

Any procedure / trigger that has a maintainability index < 20

Good code

Any procedure / trigger that has a maintainability index >= 20\.
The Maintainability Index is computed as a function:
- Lines Of Code (inverse proportional)
- the Halstead Volume
- Cyclomatic Complexity (inverse proportional).

More info

Bad code

Any procedure / trigger that is > 100 lines of code

Good code

Any procedure / trigger that is <= 100 lines of code.
A full C/AL Statement counts as 1 line of code

Docs: MESSAGE and ERROR

Mon, 01 Jan 0001 00:00:00 +0000

Always end MESSAGE or ERROR with a period.

Bad code

CustIsBlockedErr@1025 : TextConst 'ENU=You cannot %1 this type of document when Customer %2 is blocked with type %3';
...
ERROR(CustIsBlockedErr,...);

Good code

CustIsBlockedErr@1025 : TextConst 'ENU=You cannot %1 this type of document when Customer %2 is blocked with type %3.';
...
ERROR(CustIsBlockedErr,...);

Docs: Named Invocations

Mon, 01 Jan 0001 00:00:00 +0000

When calling an object statically use the name, not the number

Bad code

PAGE.RUNMODAL(525,SalesShptLine)

Good code

PAGE.RUNMODAL(PAGE::"Posted Sales Shipment Lines",SalesShptLine)

Docs: Nested WITHs

Mon, 01 Jan 0001 00:00:00 +0000

Do not nest WITHs that reference different types of objects.

Bad code

WITH PostedWhseShptLine DO BEGIN
 ...
 WITH ItemLedgEntry DO
 InsertBufferRec(...,"Serial No.","Lot No.",...);
 ...
END;

Good code

WITH PostedWhseShptLine DO BEGIN
 ...
 InsertBufferRec(...,ItemLedgEntry."Serial No.",ItemLedgEntry."Lot No.",...);
 ...
END;

Docs: One Statement Per Line

Mon, 01 Jan 0001 00:00:00 +0000

A line of code should not have more than one statement.

Bad code

IF OppEntry.FIND('-') THEN EXIT

Good code

IF OppEntry.FIND('-') THEN
 EXIT

Bad code

TotalCost += Cost; TotalAmt += Amt;

Good code

TotalCost += Cost;
TotalAmt += Amt;

Docs: Parameter Placeholders

Mon, 01 Jan 0001 00:00:00 +0000

The number of parameters passed to a string must match the placeholders.

Bad code

CannotDeleteLineErr@1005 : TextConst 'ENU=You cannot delete this line because one or more rating values exists.';
...
ERROR(CannotDeleteLineErr,TABLECAPTION);

Good code

CannotDeleteLineErr@1005 : TextConst 'ENU=You cannot delete this line because one or more rating values exists.';
...
ERROR(CannotDeleteLineErr);

Bad code

CannotUseThisFieldErr@1020 : TextConst 'ENU=You cannot use this field for %2 fields.';
...
ERROR(CannotUseThisFieldErr,0,Field.Class);

Good code

CannotUseThisFieldErr@1020 : TextConst 'ENU=You cannot use this field for %1 fields.';
...
ERROR(CannotUseThisFieldErr,Field.Class);

Docs: Readability

Mon, 01 Jan 0001 00:00:00 +0000

C/AL Coding Guidelines

Readability

Generally, all readability rules are Microsoft style choices only. You can use them to keep consistency with the existing code.

Find the C/AL guidelines by expanding the menu in the left.

Docs: Separate IF and ELSE

Mon, 01 Jan 0001 00:00:00 +0000

IF and ELSE statements should be on separate lines.

Bad code

IF Atom[i+1] = '>' THEN HasLogicalOperator := TRUE ELSE BEGIN
 ...
END;

Good code

IF Atom[i+1] = '>' THEN
 HasLogicalOperator := TRUE
ELSE BEGIN
 ...
END;

Docs: Spacing Binary Operators

Mon, 01 Jan 0001 00:00:00 +0000

There must be exactly one space character on each side of a binary operator such as = + - AND OR =. The parameter comma operator however, should have no spaces.

Bad code

"Line Discount %" := "Line Discount Amount"/"Line Value"*100

Good code

"Line Discount %" := "Line Discount Amount" / "Line Value" * 100;

Bad code

StartDate := CALCDATE('<+'+FORMAT(Days + i)+'D>', StartDate);

Good code

StartDate := CALCDATE('<+' + FORMAT(Days + i) + 'D>',StartDate);

Bad code

StartDate := 0D; // Initialize

Good code

StartDate := 0D; // Initialize

Docs: Spacing Brackets and ::

Mon, 01 Jan 0001 00:00:00 +0000

There must be no spaces characters before and after [] dimension brackets symbols or :: option symbols.

Bad code

A[i] [j] := Amt;

Good code

A[i][j] := Amt;

Bad code

"Currency Exchange Rate"."Fix Exchange Rate Amount" :: Currency:

Good code

"Currency Exchange Rate"."Fix Exchange Rate Amount"::Currency:

Bad code

IF FIND (Which) THEN

Good code

IF FIND(Which) THEN

Docs: Spacing Unary Operators

Mon, 01 Jan 0001 00:00:00 +0000

There must be no space between a unary operator and its argument (except for the NOT keyword).

Bad code

IF NOT(Type = Type::Item) THEN

Good code

IF NOT (Type = Type::Item) THEN

Bad code

DiscAmt := - "Discount Amount";

Good code

DiscAmt := -"Discount Amount";

Docs: Static Object Invocation

Mon, 01 Jan 0001 00:00:00 +0000

Call objects statically whenever possible. It reduces extra noise and removes extra variables. Downside: changing the name of the object which is called statically will need a code update.

Bad code

LOCAL PROCEDURE Code@1();
VAR
CAJnlPostBatch@1001 : Codeunit 1103;
BEGIN
CAJnlPostBatch.Run(CostJnlLine);
END;

Good code

LOCAL PROCEDURE Code@1();
BEGIN
CODEUNIT.RUN(CODEUNIT::"CA Jnl.-Post Batch",CostJnlLine);
END;

Docs: Suggested Abbreviations

Mon, 01 Jan 0001 00:00:00 +0000

Suggested Abbreviations

Whenever possible, do not use abbreviations in variables, functions and objects names.

If there is no other choice, then use the suggestions below.

Abbreviation

Text

Abs

absence

Acc

account

Acc

accounting

Accum

accumulated

Act

action

Activ

activity

Add

additional

Addr

address

Adj

adjust

Adjd

adjusted

Adjmt

adjustment

Agrmt

agreement

Alloc

allocation

Allow

allowance

Alt

alternative

Amt

amount

Amts

amounts

Ans

answer

Appl

applies

Appln

application

Arriv

arrival

Asm

assembly

ATO

assemble to order

Assgnt

assignment

Assoc

associated

Attmt

attachment

Auth

authorities

Auto

automatic

Avail

availability

Avg

average

ba db.

Bal

balance

BOM

bill of materials

Blnkt

blanket

Budg

budget

Buf

buffer

Bus

business

BIM

business interaction management

Buy

buying

Calc

calculate

Calcd

calculated

Calcu

calculation

Cal

calendar

Cap

capacity

CRP

capacity requirements planning

cash flow

cashflow

ctlg

catalog

Cat

Docs: Temporary Variable Naming

Mon, 01 Jan 0001 00:00:00 +0000

The name of a temporary variable must be prefixed with the word Temp and not otherwise.

Bad code

JobWIPBuffer@1002 : TEMPORARY Record 1018;

Good code

TempJobWIPBuffer@1002 : TEMPORARY Record 1018;

Bad code

TempJobWIPBuffer@1002 : Record 1018;

Good code

CopyOfJobWIPBuffer@1002 : Record 1018;

Docs: TextConst Suffixes

Mon, 01 Jan 0001 00:00:00 +0000

TextConst variable names should have a suffix (an approved three-letter suffix: Msg, Tok, Err, Qst, Lbl, Txt) describing usage.

Bad code

CannotDeleteLine@1005 : TextConst 'ENU=You cannot delete this line because one or more rating values exists.';
...
ERROR(CannotDeleteLine,TABLECAPTION);

Good code

CannotDeleteLineErr@1005 : TextConst 'ENU=You cannot delete this line because one or more rating values exists.';
...
ERROR(CannotDeleteLineErr,TABLECAPTION);

Bad code

Text000@1011 : TextConst 'ENU="has been changed (initial a %1: %2= %3, %4= %5)"';
...
SalesLine.FIELDERROR(Type,STRSUBSTNO(Text000,...);
...

Good code

TypeHasBeenChangedErr@1011 : TextConst 'ENU="has been changed (initial a %1: %2= %3, %4= %5)"';
...
SalesLine.FIELDERROR(Type,STRSUBSTNO(TypeHasBeenChangedErr,...);
...

Bad code

Text004@1004 : TextConst 'ENU=Indenting the Job Tasks \#1\#\#\#\#\#\#\#\#\#\#.';
...
Window@1007 : Dialog;
...
 Window.OPEN(Text004);

Good code

IndentingMsg@1004 : TextConst 'ENU=Indenting the Job Tasks \#1\#\#\#\#\#\#\#\#\#\#.';
...
Window@1007 : Dialog;
...
 Window.OPEN(IndentingMsg);

Bad code

Text002@1005 : TextConst 'ENU=You cannot delete a %1 that is used in one or more setup windows.\\ Do you want to open the G/L Account No. Where-Used List Window?';
...
IF CONFIRM(Text002,TRUE,GLAcc.TABLECAPTION) THEN

Good code

OpenWhereUsedWindowQst@1005 : TextConst 'ENU=You cannot delete a %1 that is used in one or more setup windows.\\ Do you want to open the G/L Account No. Where-Used List Window?';
...
IF CONFIRM(OpenWhereUsedWindowQst,TRUE,GLAcc.TABLECAPTION) THEN

Bad code

Selection := STRMENU(Text003,2);
...
Text003@1002 : TextConst 'ENU=&Copy dimensions from BOM,&Retrieve dimensions from components';

Good code

 Selection := STRMENU(CopyFromQst,2);
 ...
 CopyFromQst@1002 : TextConst 'ENU=&Copy dimensions from BOM,&Retrieve dimensions from components';

Bad code

DATASET
{
...
 { 1 ;1 ;Column ;Chart_of_AccountsCaption;
 SourceExpr=Chart_of_AccountsCaption }
...
Chart_of_AccountsCaption@9647 : TextConst 'ENU=Chart of Accounts';

Good code

DATASET
{
...
 { 1 ;1 ;Column ;Chart_of_AccountsCaption;
 SourceExpr=ChartOfAccountsLbl }
...
ChartOfAccountsLbl@9647 : TextConst 'ENU=Chart of Accounts';

Docs: Unary Operator Line End

Mon, 01 Jan 0001 00:00:00 +0000

Do not end a line with unary operator.

Bad code

"Quantity Handled (Base)" := -
 "Quantity Handled (Base)");

Good code

"Quantity Handled (Base)" :=
 - "Quantity Handled (Base)");

Docs: Unnecessary Compound Parenthesis

Mon, 01 Jan 0001 00:00:00 +0000

Use parenthesis only to enclose compound expressions inside compound expressions.

Bad code

IF ("Costing Method" = "Costing Method"::Standard) THEN

Good code

IF "Costing Method" = "Costing Method"::Standard THEN

Bad code

ProfitPct = -(Profit) / CostAmt * 100;

Good code

ProfitPct = -Profit / CostAmt * 100;

Docs: Unnecessary ELSE

Mon, 01 Jan 0001 00:00:00 +0000

ELSE should not be used when the last action in the THEN part is an EXIT, BREAK, SKIP, QUIT, ERROR.

Bad code

IF IsAdjmtBinCodeChanged THEN
 ERROR(AdjmtBinCodeChangeNotAllowedErr,...)
ELSE
 ERROR(BinCodeChangeNotAllowedErr,...);

Good code

IF IsAdjmtBinCodeChanged THEN
 ERROR(AdjmtBinCodeChangeNotAllowedErr,...)
ERROR(BinCodeChangeNotAllowedErr,...);

Docs: Unnecessary Function Parenthesis

Mon, 01 Jan 0001 00:00:00 +0000

Do not use parenthesis in a function call if the function does not have any parameters.

Bad code

IF ReservMgt.IsPositive() THEN

Good code

IF ReservMgt.IsPositive THEN

Bad code

IF ChangeStatusForm.RUNMODAL() <> ACTION::Yes THEN

Good code

IF ChangeStatusForm.RUNMODAL <> ACTION::Yes THEN

Docs: Unnecessary Separators

Mon, 01 Jan 0001 00:00:00 +0000

There should be no unnecessary separators.

Bad code

IF Customer.FINDFIRST THEN;;

Good code

IF Customer.FINDFIRST THEN;