Add a file to define global variables (#92)

Adds a vars.ini file to define global replacements.

.gitignore

@@ -1,4 +1,3 @@
 target/
 testing/
 _build/
-databind.toml

Cargo.toml

@@ -26,6 +26,7 @@ clap = "2.33"
 glob = "0.3"
 rand = "0.8"
 regex = "1.5"
+rust-ini = "0.17"
 same-file = "1.0"
 serde = { version="1.0", features=["derive"] }
 serde_json = "1.0"

README.md

@@ -15,6 +15,7 @@ page on the docs.
 - Shorthand to call functions without namespace prefix (`func_1` instead of `namespace:func_1`)
 - Subcommand to create new projects easily
 - While loops
+- A file to define variables that can be used anywhere
 - Variable definitions via scoreboards
 - Shorthand for objective creation
 - Shorthand for testing variables in `if` commands

docs/global_vars.rst

@@ -0,0 +1,55 @@
+Global Vars
+===========
+
+You can define global variables with a file called ``vars.ini`` in the project root.
+Keys and values aren't put in a section of the ``.ini``, they're just in the file. For example:
+
+.. code-block:: ini
+
+   name=World
+
+This defines a global variable ``name`` that can be used in your code.
+
+Using Global Vars
+-----------------
+
+To use a global variable in your code, use an ``&`` symbol followed
+by the variable name. Like this:
+
+.. code-block:: databind
+
+   say Hello, &name!
+
+Which, with the ``vars.ini`` defined above, becomes:
+
+.. code-block:: mcfunction
+
+   say Hello, World!
+
+Instances of ``&varname`` are directly replaced, meaning that
+escaping them with a ``%`` symbol doesn't work. This means that
+the following code:
+
+.. code-block:: databind
+
+   say Hello, %&name!
+
+Just becomes:
+
+.. code-block:: databind
+
+   say Hello, %World!
+
+``%World`` is effectively the same as ``World``, so the ``%`` symbol
+won't appear in the compiled output.
+
+When to use
+-----------
+
+Global variables are useful to let users more easily configure aspects
+of your datapack. This does mean that the project must be recompiled
+whenever the configuration is changed, and that users must have Databind
+downloaded to use the project. If you are only configuring number values,
+eg. an amount of time to wait for something, then it might be easier for
+people using your datapack to have a ``config.mcfunction`` file somewhere in the
+project that sets scoreboard values.

docs/index.rst

@@ -11,5 +11,6 @@ Contents:
    cli.rst
    config.rst
    macros.rst
+   global_vars.rst
    folder_structure.rst
    examples.rst

src/main.rs

@@ -18,12 +18,14 @@
 #![warn(clippy::all)]
 
 use glob::glob;
+use ini::Ini;
 use same_file::is_same_file;
 use serde::Serialize;
-use std::collections::HashMap;
-use std::env;
-use std::fs;
-use std::path::{Path, PathBuf};
+use std::{
+    collections::HashMap,
+    env, fs,
+    path::{Path, PathBuf},
+};
 use walkdir::WalkDir;
 
 mod cli;
@@ -221,6 +223,27 @@ fn main() -> std::io::Result<()> {
             src_dir.as_path()
         };
 
+        // Read vars.ini if present
+        let vars = {
+            let path = format!("{}/vars.ini", datapack);
+            let vars_ini = Path::new(&path);
+            if vars_ini.exists() && vars_ini.is_file() {
+                let i = Ini::load_from_file(vars_ini).unwrap();
+                let vars: HashMap<String, String> = i
+                    .iter()
+                    .next()
+                    .unwrap()
+                    .1
+                    .iter()
+                    // Replace each mapping of `"var": "value"` with `"&var": "value"`
+                    .map(|x| (format!("&{}", x.0), x.1.into()))
+                    .collect();
+                Some(vars)
+            } else {
+                None
+            }
+        };
+
         for entry in WalkDir::new(&src_dir).into_iter().filter_map(|e| e.ok()) {
             if entry.path().is_file() {
                 // Do not add config file to output folder
@@ -264,9 +287,17 @@ fn main() -> std::io::Result<()> {
                 }
 
                 if compile {
-                    let content = fs::read_to_string(entry.path())
-                        .expect(&format!("Failed to read file {}", entry.path().display())[..]);
-                    let mut compile = compiler::Compiler::new(content);
+                    let contents = {
+                        let mut file_contents = fs::read_to_string(entry.path())
+                            .expect(&format!("Failed to read file {}", entry.path().display())[..]);
+                        if let Some(vars_map) = &vars {
+                            for (k, v) in vars_map.iter() {
+                                file_contents = file_contents.replace(k, v);
+                            }
+                        }
+                        file_contents
+                    };
+                    let mut compile = compiler::Compiler::new(contents);
                     let tokens = compile.tokenize();
 
                     let mut compiled = if entry

tests/file_contents_tests.rs

@@ -325,3 +325,34 @@ fn test_macro_recursion() {
     let contents = fs::read_to_string(&out_path).unwrap();
     assert!(contents.contains("say Macro 1 - Test"));
 }
+
+/// Test that global variables are properly read and replaced
+#[test]
+fn test_global_vars() {
+    let mut path = tests::resources();
+    path.push("test_global_vars");
+
+    let out = TempDir::new("test_global_vars").expect("Could not create tempdir for test");
+
+    tests::run_with_args(
+        "cargo",
+        &[
+            "run",
+            "--",
+            path.to_str().unwrap(),
+            "--ignore-config",
+            "--out",
+            out.path().to_str().unwrap(),
+        ],
+        None,
+    );
+
+    let out_path = format!(
+        "{}/data/test/functions/main.mcfunction",
+        out.path().display()
+    );
+    let contents = fs::read_to_string(&out_path).unwrap();
+
+    assert!(contents.contains("say Variable 1"));
+    assert!(contents.contains("tellraw @a \"Variable 2\""));
+}

tests/resources/test_global_vars/databind.toml

@@ -0,0 +1 @@
+

tests/resources/test_global_vars/src/data/test/functions/main.databind

@@ -0,0 +1,4 @@
+func main
+    say &var1
+    tellraw @a "&var2"
+end

tests/resources/test_global_vars/vars.ini

@@ -0,0 +1,2 @@
+var1=Variable 1
+var2 = Variable 2