annotation: add `get_single_annotation` and `get_annotations`

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/annotation.nit b/src/annotation.nit
index 4daafef..d4a13ac 100644 (file)
--- a/src/annotation.nit
+++ b/src/annotation.nit
@@ -19,6 +19,37 @@ import parser
 import modelbuilder
 import literal
 
+redef class Prod
+       super ANode
+
+       # Try to get its single annotation with a given name
+       # If there is no such an annotation, null is returned.
+       # If there is more than one annotation, a error message is printed and the first annotation is returned
+       fun get_single_annotation(name: String, modelbuilder: ModelBuilder): nullable AAnnotation
+       do
+               var res = get_annotations(name)
+               if res.is_empty then return null
+               if res.length > 1 then
+                       modelbuilder.error(res[1], "Error: multiple annotation `{name}`. A previous one is defined line {res[0].location.line_start}")
+               end
+               return res.first
+       end
+
+       # Return all its annotations of a given name in the order of their declaration
+       # Retun an empty array if no such an annotation.
+       fun get_annotations(name: String): Array[AAnnotation]
+       do
+               var res = new Array[AAnnotation]
+               var nas = n_annotations
+               if nas == null then return res
+               for na in nas.n_items do
+                       if na.name != name then continue
+                       res.add(na)
+               end
+               return res
+       end
+end
+
 redef class AAnnotation
        # The name of the annotation
        fun name: String