Move template rendering and themes onto PluginHost (#559)

crates/yaak-commands/src/render.rs

@@ -0,0 +1,30 @@
+//! Rendering a template against an environment chain.
+//!
+//! The variables come from the chain, the functions come from the host's
+//! template callback. Neither of these knows which host it is running under —
+//! that is the whole point of taking the callback as a parameter.
+
+use serde_json::Value;
+use yaak_models::models::Environment;
+use yaak_models::render::make_vars_hashmap;
+use yaak_templates::{RenderOptions, TemplateCallback, parse_and_render, render_json_value_raw};
+
+pub async fn render_template<T: TemplateCallback>(
+    template: &str,
+    environment_chain: Vec<Environment>,
+    cb: &T,
+    opt: &RenderOptions,
+) -> yaak_templates::error::Result<String> {
+    let vars = &make_vars_hashmap(environment_chain);
+    parse_and_render(template, vars, cb, opt).await
+}
+
+pub async fn render_json_value<T: TemplateCallback>(
+    value: Value,
+    environment_chain: Vec<Environment>,
+    cb: &T,
+    opt: &RenderOptions,
+) -> yaak_templates::error::Result<Value> {
+    let vars = &make_vars_hashmap(environment_chain);
+    render_json_value_raw(value, vars, cb, opt).await
+}