Don't introduce too many helper types for input and output

[rakyll]

The current API surface is extremely confusing for GenerateContent because it introduces a wide range of indirection with helper types such as:

- Contents
- Texts
- PartSlice
- ContentSlice

As a user, it's hard for me to understand what's actually supported here without reading the library implementation. Remove all of these types and stick to []Content as inputs and outputs. The following code isn't very hard to write:

GenerateContentStream(ctx, "model", []genai.Content{{Parts: parts}}, nil)

The helper types don't help the average Go user because we like orthogonality and less magic. A little bit verbosity is ok to remove indirection.

[happy-qiao]

Thanks for the feedback. I'd also like to hear what @eliben and @jba think.

[happy-qiao]

GenerateContentStream(ctx, "model", []genai.Content{{Parts: parts}}, nil)
GenerateContentStream(ctx, "model", genai.Text("hello").ToContents(), nil)

We can support both. @rakyll What do you think?

[jba]

Is there any Content that's not a list of Parts?
In github.com/google/generative-ai-go/genai, we just use a []Part. What can you do with this API that you can't with that?

[happy-qiao]

There is Role field in the Content. If we use []Part, how to pass the Role field in? And how to ensure future proof.

[jba]

OK. That isn't really clear from the doc. For example, here is the doc for Text:

I wouldn't guess from that that I can only use Text for the user role. If I'm doing a session and want to send a model response back to the model (roleModel), it would be wrong to use Text.

Separately from that, would it simplify things if the argument to GenerateContent was []Content, and you got rid of the XXXSlice types?

[happy-qiao]

https://pkg.go.dev/google.golang.org/genai#Models.GenerateContent

func (m Models) GenerateContent(ctx context.Context, model string, contents []*Content, config GenerateContentConfig) (GenerateContentResponse, error)

We have changed the API surface change to []*Content type.