Allow process path values and targets as buildscript program names

Also deduce the recipe name.

1 files changed, 45 insertions, 2 deletions

diff --git a/libbuild2/build/script/parser.hxx b/libbuild2/build/script/parser.hxx
index 5f08209..15d4ede 100644
--- a/libbuild2/build/script/parser.hxx
+++ b/libbuild2/build/script/parser.hxx
@@ -34,8 +34,9 @@ namespace build2
         // name.
         //
         script
-        pre_parse (istream&, const path_name&, uint64_t line,
-                   optional<string> diag);
+        pre_parse (const target&,
+                   istream&, const path_name&, uint64_t line,
+                   optional<string> diag, const location& diag_loc);
 
         // Recursive descent parser.
         //
@@ -82,9 +83,51 @@ namespace build2
         virtual lookup
         lookup_variable (name&&, string&&, const location&) override;
 
+        // During execution translate the process path and executable targets
+        // leaving the rest for the base parser to handle.
+        //
+        // During pre-parsing try to deduce the low-verbosity script
+        // diagnostics name.
+        //
+        virtual optional<process_path>
+        parse_program (token&, build2::script::token_type&, names&) override;
+
+        void
+        parse_program_diag (token&, build2::script::token_type&, names&);
+
       protected:
         script* script_;
 
+        // Current low-verbosity script diagnostics name and weight.
+        //
+        // During pre-parsing each command leading names are translated into a
+        // potential script name, unless it is set manually (with the diag
+        // directive or via the constructor). The potential script name has a
+        // weight associated with it, so script names with greater weights
+        // override names with lesser weights. The possible weights are:
+        //
+        // 0     - builtins that do not add to the script semantics (exit,
+        //         true, etc) and are never picked up as a script name
+        //
+        // [1 2] - other builtins
+        //
+        // 3     - process path or executable target
+        //
+        // 4     - manually set names
+        //
+        // If two potential script names with the same weights are encountered
+        // then this ambiguity is reported unless a higher-weighted name is
+        // encountered later.
+        //
+        optional<pair<string, location>> diag;
+        optional<pair<string, location>> diag2;
+        uint8_t                          diag_weight = 0;
+
+        // True during pre-parsing when the pre-parse mode is temporarily
+        // suspended to perform expansion.
+        //
+        bool pre_parse_suspended_ = false;
+
         // Execute state.
         //
         runner* runner_;