I want to iterate over the JSON using CTFE. I have tried both std.json and vibe.data.json, but there is no luck. I am not sure what I am missing.
import std.stdio;
import std.json;
import std.array;
import vibe.data.json;
void main()
{
enum string config = `{ "ModelNames": [ "Bank", "Biller", "Aggregator" ] }`;
const auto c1 = parseJSON(config);
immutable auto c2 = parseJsonString(config);
foreach (key; c1["ModelNames"].array)
writeln(key.get!string);
foreach (key; c2["ModelNames"])
writeln(key.get!string);
// static foreach (key; c1["ModelNames"].array)
// pragma(msg, key.get!string);
// static foreach (key; c2["ModelNames"])
// pragma(msg, key.get!string);
}
Wrap your logic into a regular D function, then get the compiler to evaluate it at compile-time by calling it is a context where the result must be known at compile-time, such as using the result in an enum
:
import std.algorithm.iteration;
import std.stdio;
import std.json;
import std.array;
void main()
{
enum string config = `{ "ModelNames": [ "Bank", "Biller", "Aggregator" ] }`;
static string[] getModelNames(string json)
{
auto c1 = parseJSON(json);
return c1["ModelNames"].array.map!(item => item.str).array;
}
enum string[] modelNames = getModelNames(config);
pragma(msg, modelNames);
}