From fba03c4fb6b4b04788dfc4993ebc18d8ad20e436 Mon Sep 17 00:00:00 2001
From: Johan Hidding <j.hidding@esciencecenter.nl>
Date: Tue, 9 Jul 2024 13:07:52 +0200
Subject: [PATCH] create an alias for code blocks that have both file and id
 tags; fix #46

---
 entangled/document.py           |  6 +++
 entangled/markdown_reader.py    |  6 +++
 entangled/tangle.py             |  3 ++
 test/test_id_and_file_target.py | 70 +++++++++++++++++++++++++++++++++
 4 files changed, 85 insertions(+)
 create mode 100644 test/test_id_and_file_target.py

diff --git a/entangled/document.py b/entangled/document.py
index 9c35ad5..26ee2e2 100644
--- a/entangled/document.py
+++ b/entangled/document.py
@@ -57,11 +57,17 @@ class ReferenceMap:
         default_factory=lambda: defaultdict(list)
     )
     targets: set[str] = field(default_factory=set)
+    alias: dict[str, str] = field(default_factory=dict)
 
     def names(self) -> Iterable[str]:
         return self.index.keys()
 
     def by_name(self, n: str) -> Iterable[CodeBlock]:
+        if n not in self.index and n not in self.alias:
+            raise AttributeError(name=n, obj=self)
+        if n not in self.index:
+            return self.by_name(self.alias[n])
+
         return (self.map[r] for r in self.index[n])
 
     def new_id(self, filename: str, name: str) -> ReferenceId:
diff --git a/entangled/markdown_reader.py b/entangled/markdown_reader.py
index 6c974a1..fb308d5 100644
--- a/entangled/markdown_reader.py
+++ b/entangled/markdown_reader.py
@@ -130,6 +130,12 @@ def on_close_codeblock(self, m: re.Match):
             self.reference_map[ref] = code
             if target_file is not None:
                 self.reference_map.targets.add(target_file)
+
+            # when both target_file and block_id are given,
+            # make an alias
+            if target_file is not None and block_id is not None:
+                self.reference_map.alias[target_file] = block_id
+
             self.content.append(ref)
             self.current_content = []
 
diff --git a/entangled/tangle.py b/entangled/tangle.py
index 31033f4..c2d11d6 100644
--- a/entangled/tangle.py
+++ b/entangled/tangle.py
@@ -119,6 +119,9 @@ def tangle_ref(
     if annotation is None:
         annotation = config.annotation
 
+    if ref_name in refs.alias:
+        ref_name = refs.alias[ref_name]
+
     if ref_name not in refs:
         raise KeyError(ref_name)
     v = _visited or Visitor()
diff --git a/test/test_id_and_file_target.py b/test/test_id_and_file_target.py
new file mode 100644
index 0000000..2f35c60
--- /dev/null
+++ b/test/test_id_and_file_target.py
@@ -0,0 +1,70 @@
+from entangled.markdown_reader import MarkdownReader
+from entangled.tangle import tangle_ref, AnnotationMethod
+
+md_in = """
+``` {.rust file=test1.rs #blockid1}
+fn main() {
+    println!("Hello, World!");
+}
+```
+
+``` {.rust #blockid2 file=test2.rs}
+fn main() {
+    println!("Hello, World!");
+}
+```
+
+``` {.rust #blockid3 file=test3.rs}
+fn fac(i: u64) -> u64 {
+    result: u64 = 1;
+    for j in 1..i {
+        result *= j;
+    }
+    return result;
+}
+```
+
+``` {.rust #blockid3}
+fn main() {
+    println!("42! = {}", fac(42));
+}
+```
+"""
+
+result1_out = result2_out = """
+fn main() {
+    println!("Hello, World!");
+}
+"""
+
+result3_out = """
+fn fac(i: u64) -> u64 {
+    result: u64 = 1;
+    for j in 1..i {
+        result *= j;
+    }
+    return result;
+}
+fn main() {
+    println!("42! = {}", fac(42));
+}
+"""
+
+def test_id_and_file_target():
+    mr = MarkdownReader("-")
+    mr.run(md_in)
+
+    content1, _ = tangle_ref(mr.reference_map, "blockid1", AnnotationMethod.NAKED)
+    assert content1.strip() == result1_out.strip()
+    content2, _ = tangle_ref(mr.reference_map, "blockid2", AnnotationMethod.NAKED)
+    assert content2.strip() == result2_out.strip()
+    content3, _ = tangle_ref(mr.reference_map, "blockid3", AnnotationMethod.NAKED)
+    assert content3.strip() == result3_out.strip()
+
+    assert mr.reference_map.targets == {"test1.rs", "test2.rs", "test3.rs"}
+    for i in range(1, 4):
+        ref = f"test{i}.rs"
+        bid = f"blockid{i}"
+        c, _ = tangle_ref(mr.reference_map, ref, AnnotationMethod.NAKED)
+        d, _ = tangle_ref(mr.reference_map, ref, AnnotationMethod.NAKED)
+        assert c == d