Add support for importing template files with macros (#51)

* Fix review comments for macro imports

3 files changed, 62 insertions, 4 deletions

diff --git a/askama_shared/src/generator.rs b/askama_shared/src/generator.rs
index e92a2c6..e135c13 100644
--- a/askama_shared/src/generator.rs
+++ b/askama_shared/src/generator.rs
@@ -12,8 +12,8 @@ use std::collections::{HashMap, HashSet};
 use syn;
 
 
-pub fn generate(input: &TemplateInput, nodes: &[Node]) -> String {
-    Generator::default().build(&State::new(input, nodes))
+pub fn generate(input: &TemplateInput, nodes: &[Node], imported: &HashMap<&str, Macro>) -> String {
+    Generator::default().build(&State::new(input, nodes, imported))
 }
 
 struct State<'a> {
@@ -26,7 +26,7 @@ struct State<'a> {
 }
 
 impl<'a> State<'a> {
-    fn new<'n>(input: &'n TemplateInput, nodes: &'n [Node]) -> State<'n> {
+    fn new<'n>(input: &'n TemplateInput, nodes: &'n [Node], imported: &'n HashMap<&'n str, Macro<'n>>) -> State<'n> {
         let mut base: Option<&Expr> = None;
         let mut blocks = Vec::new();
         let mut macros = HashMap::new();
@@ -47,6 +47,9 @@ impl<'a> State<'a> {
                 _ => {},
             }
         }
+        for (name, ref m) in imported {
+            macros.insert(name, m);
+        }
         State {
             input,
             nodes,
@@ -351,6 +354,7 @@ impl<'a> Generator<'a> {
                 },
                 Node::Call(ref ws, name, ref args) => self.write_call(state, ws, name, args),
                 Node::Macro(_, _) |
+                Node::Import(_, _) |
                 Node::Extends(_) => {
                     if let AstLevel::Nested = level {
                         panic!("macro or extend blocks only allowed at the top level");
diff --git a/askama_shared/src/lib.rs b/askama_shared/src/lib.rs
index 066faca..a7deaff 100644
--- a/askama_shared/src/lib.rs
+++ b/askama_shared/src/lib.rs
@@ -21,7 +21,11 @@ mod input;
 mod parser;
 
 use input::Print;
+use parser::{Node, Macro};
 
+use std::borrow::Cow;
+use std::collections::HashMap;
+use std::path::Path;
 
 /// Takes a `syn::DeriveInput` and generates source code for it
 ///
@@ -33,16 +37,53 @@ use input::Print;
 pub fn build_template(ast: &syn::DeriveInput) -> String {
     let data = input::TemplateInput::new(ast);
     let nodes = parser::parse(data.source.as_ref());
+    let imports = Imports::new(&nodes, &data.path);
+    let imported = imports.parse();
     if data.meta.print == Print::Ast || data.meta.print == Print::All {
         println!("{:?}", nodes);
     }
-    let code = generator::generate(&data, &nodes);
+    let code = generator::generate(&data, &nodes, &imported);
     if data.meta.print == Print::Code || data.meta.print == Print::All {
         println!("{}", code);
     }
     code
 }
 
+
+pub struct Imports<'a> {
+    pub sources: Vec<Cow<'a, str>>
+}
+
+impl <'a> Imports<'a> {
+    pub fn new(parent_nodes: &'a [Node], parent_path: &'a Path) -> Imports<'a> {
+        let sources = parent_nodes.iter().filter_map(|n| {
+            match *n {
+                Node::Import(_, ref import_path) => {
+                    let path = path::find_template_from_path(import_path, Some(parent_path));
+                    let src = path::get_template_source(&path);
+                    Some(Cow::Owned(src))
+                },
+                _ => None,
+            }
+        }).collect();
+        Imports {
+            sources,
+        }
+    }
+
+    pub fn parse(&'a self) -> HashMap<&'a str, Macro<'a>> {
+        self.sources.iter()
+            .flat_map(|s| parser::parse(s.as_ref()))
+            .filter_map(|n| {
+                match n {
+                    Node::Macro(name, m) => Some((name, m)),
+                    _ => None,
+                }})
+            .collect()
+    }
+}
+
+
 mod errors {
     error_chain! {
         foreign_links {
diff --git a/askama_shared/src/parser.rs b/askama_shared/src/parser.rs
index ab79a31..083e96b 100644
--- a/askama_shared/src/parser.rs
+++ b/askama_shared/src/parser.rs
@@ -42,6 +42,7 @@ pub enum Node<'a> {
     Extends(Expr<'a>),
     BlockDef(WS, &'a str, Vec<Node<'a>>, WS),
     Include(WS, &'a str),
+    Import(WS, &'a str),
     Macro(&'a str, Macro<'a>),
 }
 
@@ -388,6 +389,17 @@ named!(block_include<Node>, do_parse!(
     }))
 ));
 
+named!(block_import<Node>, do_parse!(
+    pws: opt!(tag_s!("-")) >>
+    ws!(tag_s!("import")) >>
+    name: ws!(expr_str_lit) >>
+    nws: opt!(tag_s!("-")) >>
+    (Node::Import(WS(pws.is_some(), nws.is_some()), match name {
+        Expr::StrLit(s) => s,
+        _ => panic!("import path must be a string literal"),
+    }))
+));
+
 named!(block_macro<Node>, do_parse!(
     pws1: opt!(tag_s!("-")) >>
     ws!(tag_s!("macro")) >>
@@ -420,6 +432,7 @@ named!(block_node<Node>, do_parse!(
         block_for |
         block_extends |
         block_include |
+        block_import |
         block_block |
         block_macro
     ) >>