xapian: Wrap FieldProcessor.

* xapian.i.in (GuileXapianFieldProcessorWrapper): New class.
* xapian/xapian.scm (field-processor): New public function.

1 files changed, 32 insertions, 1 deletions

diff --git a/xapian.i.in b/xapian.i.in
index ff4ce80..bc9991c 100644
--- a/xapian.i.in
+++ b/xapian.i.in
@@ -1,5 +1,5 @@
 /* guile-xapian --- Guile bindings for Xapian
- * Copyright © 2020, 2023 Arun Isaac <arunisaac@systemreboot.net>
+ * Copyright © 2020, 2023–2024 Arun Isaac <arunisaac@systemreboot.net>
  * Copyright © 2021, 2022 Bob131 <bob@bob131.so>
  *
  * This file is part of guile-xapian.
@@ -141,3 +141,34 @@
     return new Xapian::Query (op_, slot, range_lower, range_upper);
   }
 }
+
+// Child class of Xapian::FieldProcessor that calls back to a
+// user-specified Scheme procedure to process fields.
+%{
+  class GuileXapianFieldProcessorWrapper
+    : public Xapian::FieldProcessor {
+  private:
+    SCM proc;
+  public:
+    GuileXapianFieldProcessorWrapper(SCM _proc) {
+      proc = _proc;
+    }
+    Xapian::Query operator()(const std::string &str) {
+      void *ptr;
+      int res = SWIG_ConvertPtr(scm_call_1(proc, scm_from_utf8_string(str.c_str())),
+                                &ptr,
+                                SWIGTYPE_p_Xapian__Query,
+                                0);
+      return *((Xapian::Query*)ptr);
+    }
+  };
+%}
+
+class GuileXapianFieldProcessorWrapper
+: public Xapian::FieldProcessor
+{
+ public:
+  GuileXapianFieldProcessorWrapper(SCM);
+  ~GuileXapianFieldProcessorWrapper();
+  Xapian::Query operator()(std::string const&);
+};