Using Custom functions

[MPRDD]

Hi.
I'm evaluating this incredible engine, to see if to use it for a rewite of direct debit xml generator I wrote years ago.

It's clear that the custom function mechanism works perfectly, but I think there is something in the concept of a context that I must be missing.

Any clarifying hints would be greatly appreciated.

---

program Console;

{$APPTYPE CONSOLE}
{$R *.res}

uses
System.SysUtils,
System.IOUtils,
Sempare.Template,
Sempare.Template.Context;

type
rPerson = record
FirstName: string;
LastName: string;
end;

TFunctions = class
public
class function FullName(const FirstName, LastName: string): string; static;
end;

class function TFunctions.FullName(const FirstName, LastName: string): string;
function ProperCase(aText: string): string;
begin
aText := trim(aText);
result := uppercase(aText[1]) + lowercase(Copy(aText, 2));
end;

begin
result := ProperCase(FirstName) + ' ' + ProperCase(LastName);
end;

var
me: rPerson;
ctx: ITemplateContext;

const
strMeTemplate = '<% FullName(_.FirstName, _.LastName) %>';

begin
try
me.FirstName := 'FIRSTNAME';
me.LastName := 'LASTNAME';

ctx := Template.Context([eoOptimiseTemplate, eoPrettyPrint]);
ctx.Functions.AddFunctions(TFunctions);

// case 1 OK
writeln(Template.Eval(ctx, strMeTemplate, me));

// ensure template file content is the same as strMeTemplate
TFile.WriteAllText('.\templates\meTemplate.tpl', strMeTemplate);

// case 2 KO ???
writeln(Template.Eval(ctx, Template.Parse(TFile.ReadAllText('.\templates\meTemplate.tpl')), me));

readln;

except
on E: Exception do
Writeln(E.ClassName, ': ', E.Message);
end;

end.

[darnocian]

The parser does attempt some validation on the function calls, so it also requires the context.

Change:

// case 2 KO ???
writeln(Template.Eval(ctx, Template.Parse(TFile.ReadAllText('.\templates\meTemplate.tpl')), me));

to

writeln(Template.Eval(ctx, Template.Parse(ctx, TFile.ReadAllText('.\templates\meTemplate.tpl')), me));

[darnocian]

Also, I'd recommend trying to use the template registry. It removes most of the boiler plate around loading from templates.

It has a single context that you can access Template.Resolver.Context.
When you use Template.Resolve('template.tpl', data), it will resolve from a templates directory automatically. There is a Template.Resolver.TemplateDir that you can use to customise the location if required.

[darnocian]

FYI

https://github.com/sempare/sempare-delphi-template-engine/blob/main/docs/template-registry.md

https://dev.to/sempare/the-sempare-template-engine-advanced-template-registry-features-29o9

[MPRDD]

Thank you very much for your prompt and enlightening answer.
I'll certainly end up using the registry.