feat: add support for include and inherit (#9)

* Flag to parse everything in the same path as the template
* Logic for 'include' flag
* Option to define a different 'include' path
* Logic for `include-path` option
* Document new `--include` flag and `--include-path` option
* Update **tera cli** usage documentation
* Tera's **include** example
* Tera's **inheritance** example
* Update markdown README file

Author: tandiljuan

README.md

@@ -125,6 +125,12 @@ By default, your ENV variables will be loaded at the root of the context data. F
 
 While the syntax is a little more verbose, paired with `--fail-on-collision`, this option allows ensuring that nothing happens in your back.
 
+### External files
+
+Using the `--include` flag, the command will scan recursively for files that could be [included](https://tera.netlify.app/docs/#include), used as [macros](https://tera.netlify.app/docs/#macros) or for [inheritance](https://tera.netlify.app/docs/#inheritance). By default, it will scan the folder where the main template is located, unless the `--include-path` option is given.
+
+From this repository, you can test **include** feature with the command `USER="[YOURNAME]" tera --template data/include/hello.txt --include --env-only` and test **inheritance** feature with `USER="[YOURNAME]" tera --template data/inheritance/child.txt --inherit --env-only`.
+
 ### Output
 
 By default,
@@ -159,13 +165,20 @@ Passing the `-a | --escape` flag allows escaping the content.
                                    be raised
             --fail-on-collision    if you prefer your data to override the ENV
         -h, --help                 Prints help information
+        -i, --include              This flag tells the command to parse all templates found in the same
+                                   path where the given template is located [aliases: inherit]
         -s, --stdin                The context data can be passed using stdin
         -V, --version              Prints version information
 
     OPTIONS:
-            --env-key <env-key>      By default, if --env is set, the environment variables will be
-                                     attached at the root of the context. This is convenient but may end
-                                     up conflicting with your data. To prevent collisions, you can
-                                     provide a custom key with this option
-        -o, --out <out>              Optional output file. If not passed, using stdout
-        -t, --template <template>    Location of the template
+            --env-key <env-key>
+                By default, if --env is set, the environment variables will be attached at the root of
+                the context. This is convenient but may end up conflicting with your data. To prevent
+                collisions, you can provide a custom key with this option
+
+            --include-path <include-path>
+                Option to define a different path from which search and parse templates [aliases:
+                inherit-path]
+
+        -o, --out <out>                      Optional output file. If not passed, using stdout
+        -t, --template <template>            Location of the template

README_src.adoc

@@ -99,6 +99,12 @@ By default, your ENV variables will be loaded at the root of the context data. F
 
 While the syntax is a little more verbose, paired with `--fail-on-collision`, this option allows ensuring that nothing happens in your back.
 
+=== External files
+
+Using the `--include` flag, the command will scan recursively for files that could be https://tera.netlify.app/docs/#include[included], used as https://tera.netlify.app/docs/#macros[macros] or for https://tera.netlify.app/docs/#inheritance[inheritance]. By default, it will scan the folder where the main template is located, unless the `--include-path` option is given.
+
+From this repository, you can test *include* feature with the command `USER="[YOURNAME]" tera --template data/include/hello.txt --include --env-only` and test *inheritance* feature with `USER="[YOURNAME]" tera --template data/inheritance/child.txt --inherit --env-only`.
+
 === Output
 
 By default, 

data/include/hello.txt

@@ -0,0 +1,2 @@
+Hello {{ USER }}, this is the Hello template.
+{% include "world.txt" %}

data/include/world.txt

@@ -0,0 +1 @@
+This is the world template.

data/inheritance/base.txt

@@ -0,0 +1,7 @@
+This is a BASE template.
+
+The default greetings shows "Greetings!" but we can improve that with inheritance!
+
+{% block greetings %}
+Greetings!
+{% endblock greetings %}

data/inheritance/child.txt

@@ -0,0 +1,7 @@
+{% extends "base.txt" %}
+
+The following block will replace our greetings in the base.
+
+{% block greetings %}
+May the force be with you **{{ USER }}**
+{% endblock greetings %}

doc/usage.adoc

@@ -22,13 +22,20 @@ FLAGS:
                                be raised
         --fail-on-collision    if you prefer your data to override the ENV
     -h, --help                 Prints help information
+    -i, --include              This flag tells the command to parse all templates found in the same
+                               path where the given template is located [aliases: inherit]
     -s, --stdin                The context data can be passed using stdin
     -V, --version              Prints version information
 
 OPTIONS:
-        --env-key <env-key>      By default, if --env is set, the environment variables will be
-                                 attached at the root of the context. This is convenient but may end
-                                 up conflicting with your data. To prevent collisions, you can
-                                 provide a custom key with this option
-    -o, --out <out>              Optional output file. If not passed, using stdout
-    -t, --template <template>    Location of the template
+        --env-key <env-key>
+            By default, if --env is set, the environment variables will be attached at the root of
+            the context. This is convenient but may end up conflicting with your data. To prevent
+            collisions, you can provide a custom key with this option
+
+        --include-path <include-path>
+            Option to define a different path from which search and parse templates [aliases:
+            inherit-path]
+
+    -o, --out <out>                      Optional output file. If not passed, using stdout
+    -t, --template <template>            Location of the template

src/main.rs

@@ -7,7 +7,7 @@ use clap::{crate_name, crate_version, Clap};
 use env_logger::Env;
 use log::{debug, info, trace};
 use opts::*;
-use std::{fs::File, io::Write};
+use std::{fs::canonicalize, fs::File, io::Write, string::String};
 use tera::{Context, Tera};
 
 fn main() -> Result<(), String> {
@@ -22,14 +22,47 @@ fn main() -> Result<(), String> {
 
 	let autoescape = opts.autoescape;
 	let output = opts.out.to_owned();
+	let mut include = opts.include;
+	let mut path = canonicalize(&opts.template).unwrap();
+
+	if opts.include_path.is_some() {
+		include = true;
+		path = canonicalize(opts.include_path.as_ref().unwrap()).unwrap();
+	}
 
 	let mut wrapped_context = wrapped_context::WrappedContext::new(opts);
 	wrapped_context.create_context();
 
 	let context: &Context = wrapped_context.context();
 	trace!("context:\n{:#?}", context);
 
-	let rendered = Tera::one_off(&template, context, autoescape).unwrap();
+	let rendered;
+
+	if include {
+		let mut dir = path.to_str().unwrap();
+
+		if path.is_file() {
+			dir = path.parent().unwrap().to_str().unwrap();
+		}
+
+		let glob = dir.to_owned() + "/**/*";
+
+		let mut tera = match Tera::new(&glob) {
+			Ok(t) => t,
+			Err(e) => {
+				println!("Parsing error(s): {}", e);
+				::std::process::exit(1);
+			}
+		};
+
+		if !autoescape {
+			tera.autoescape_on(vec![]);
+		}
+
+		rendered = tera.render_str(&template, context).unwrap();
+	} else {
+		rendered = Tera::one_off(&template, context, autoescape).unwrap();
+	}
 
 	println!("{}", rendered);
 

src/opts.rs

@@ -11,6 +11,15 @@ pub struct Opts {
 	#[clap(short, long)]
 	pub template: PathBuf,
 
+	/// This flag tells the command to parse all templates found in the same
+	/// path where the given template is located.
+	#[clap(short, long, visible_alias = "inherit")]
+	pub include: bool,
+
+	/// Option to define a different path from which search and parse templates.
+	#[clap(long, visible_alias = "inherit-path")]
+	pub include_path: Option<PathBuf>,
+
 	/// Location of the context data. This file can be of the following type:
 	/// json | toml | yaml. If you prefer to pass the data as stdin, use `--stdin`
 	#[clap(index = 1, required_unless_present_any = &["stdin", "env-only"], conflicts_with = "env-only")]