Merge pull request #2724 from crystal-lang/feature/macros_in_lib

Compiler: allow using macros inside lib declarations. Part of #2710
crystal-lang · Jun 2, 2016 · 93ac92f · 93ac92f
2 parents 5fcfdd7 + 6d540a7
commit 93ac92f
Showing 6 changed files with 108 additions and 21 deletions.
diff --git a/spec/compiler/parser/parser_spec.cr b/spec/compiler/parser/parser_spec.cr
@@ -644,6 +644,12 @@ describe "Parser" do
 
   it_parses "fun foo(x : Int32) : Int64\nx\nend", FunDef.new("foo", [Arg.new("x", restriction: "Int32".path)], "Int64".path, body: "x".var)
 
+  it_parses "lib LibC; {{ 1 }}; end", LibDef.new("LibC", body: [MacroExpression.new(1.int32)] of ASTNode)
+  it_parses "lib LibC; {% if 1 %}2{% end %}; end", LibDef.new("LibC", body: [MacroIf.new(1.int32, MacroLiteral.new("2"))] of ASTNode)
+
+  it_parses "lib LibC; struct Foo; {{ 1 }}; end; end", LibDef.new("LibC", body: StructDef.new("Foo", Expressions.from([MacroExpression.new(1.int32)] of ASTNode)))
+  it_parses "lib LibC; struct Foo; {% if 1 %}2{% end %}; end; end", LibDef.new("LibC", body: StructDef.new("Foo", Expressions.from([MacroIf.new(1.int32, MacroLiteral.new("2"))] of ASTNode)))
+
   it_parses "1 .. 2", RangeLiteral.new(1.int32, 2.int32, false)
   it_parses "1 ... 2", RangeLiteral.new(1.int32, 2.int32, true)
 

diff --git a/spec/compiler/type_inference/lib_spec.cr b/spec/compiler/type_inference/lib_spec.cr
@@ -819,4 +819,30 @@ describe "Type inference: lib" do
       LibFoo.foo
       )) { |mod| mod.nil }
   end
+
+  it "can use macros inside lib" do
+    assert_type(%(
+      lib LibFoo
+        {% begin %}
+          fun foo : Int32
+        {% end %}
+      end
+
+      LibFoo.foo
+      )) { int32 }
+  end
+
+  it "can use macros inside struct" do
+    assert_type(%(
+      lib LibFoo
+        struct Foo
+          {% begin %}
+            x : Int32
+          {% end %}
+        end
+      end
+
+      LibFoo::Foo.new.x
+      )) { int32 }
+  end
 end
diff --git a/src/compiler/crystal/macros/macros.cr b/src/compiler/crystal/macros/macros.cr
@@ -1,4 +1,11 @@
 module Crystal
+  # How code generated by macro should be parsed
+  enum MacroExpansionMode
+    Normal        = 0
+    Lib           = 1
+    StructOrUnion = 2
+  end
+
   class Program
     def expand_macro(a_macro : Macro, call : Call, scope : Type, type_lookup : Type?)
       macro_expander.expand a_macro, call, scope, type_lookup || scope
@@ -8,8 +15,17 @@ module Crystal
       macro_expander.expand node, scope, type_lookup || scope, free_vars
     end
 
-    def parse_macro_source(expanded_macro, the_macro, node, vars, inside_def = false, inside_type = false, inside_exp = false)
-      parse_macro_source expanded_macro, the_macro, node, vars, inside_def, inside_type, inside_exp, &.parse
+    def parse_macro_source(expanded_macro, the_macro, node, vars, inside_def = false, inside_type = false, inside_exp = false, mode : MacroExpansionMode = MacroExpansionMode::Normal)
+      parse_macro_source(expanded_macro, the_macro, node, vars, inside_def, inside_type, inside_exp) do |parser|
+        case mode
+        when .lib?
+          parser.parse_lib_body
+        when .struct_or_union?
+          parser.parse_struct_or_union_body
+        else
+          parser.parse
+        end
+      end
     end
 
     def parse_macro_source(expanded_macro, the_macro, node, vars, inside_def = false, inside_type = false, inside_exp = false)

diff --git a/src/compiler/crystal/semantic/base_type_visitor.cr b/src/compiler/crystal/semantic/base_type_visitor.cr
@@ -571,17 +571,24 @@ module Crystal
       true
     end
 
-    def expand_macro(the_macro, node)
+    def expand_macro(the_macro, node, mode = nil)
       begin
         expanded_macro = yield
       rescue ex : Crystal::Exception
         node.raise "expanding macro", ex
       end
 
+      mode ||= if @lib_def_pass > 0
+                 MacroExpansionMode::Lib
+               else
+                 MacroExpansionMode::Normal
+               end
+
       generated_nodes = @mod.parse_macro_source(expanded_macro, the_macro, node, Set.new(@vars.keys),
         inside_def: !!@typed_def,
         inside_type: !current_type.is_a?(Program),
         inside_exp: @exp_nest > 0,
+        mode: mode,
       )
 
       if node_doc = node.doc
@@ -633,7 +640,7 @@ module Crystal
       expand_inline_macro node
     end
 
-    def expand_inline_macro(node)
+    def expand_inline_macro(node, mode = nil)
       if expanded = node.expanded
         begin
           expanded.accept self
@@ -645,7 +652,7 @@ module Crystal
 
       the_macro = Macro.new("macro_#{node.object_id}", [] of Arg, node).at(node.location)
 
-      generated_nodes = expand_macro(the_macro, node) do
+      generated_nodes = expand_macro(the_macro, node, mode: mode) do
         @mod.expand_macro node, (@scope || current_type), @type_lookup, @free_vars
       end
 

diff --git a/src/compiler/crystal/semantic/top_level_visitor.cr b/src/compiler/crystal/semantic/top_level_visitor.cr
@@ -1002,6 +1002,12 @@ module Crystal
         false
       end
 
+      def visit(node : MacroIf | MacroFor | MacroExpression)
+        @type_inference.expand_inline_macro(node, mode: MacroExpansionMode::StructOrUnion)
+        node.expanded.not_nil!.accept self
+        false
+      end
+
       def visit(node : ASTNode)
         true
       end

diff --git a/src/compiler/crystal/syntax/parser.cr b/src/compiler/crystal/syntax/parser.cr
@@ -872,19 +872,9 @@ module Crystal
       when :"{"
         parse_hash_or_tuple_literal
       when :"{{"
-        macro_exp = parse_macro_expression
-        check_macro_expression_end
-        next_token
-        MacroExpression.new(macro_exp)
+        parse_percent_macro_expression
       when :"{%"
-        macro_control = parse_macro_control(@line_number, @column_number)
-        if macro_control
-          check :"%}"
-          next_token_skip_space
-          macro_control
-        else
-          unexpected_token_in_atomic
-        end
+        parse_percent_macro_control
       when :"::"
         parse_ident_or_global_call
       when :"->"
@@ -2693,6 +2683,13 @@ module Crystal
       end
     end
 
+    def parse_percent_macro_expression
+      macro_exp = parse_macro_expression
+      check_macro_expression_end
+      next_token
+      MacroExpression.new(macro_exp)
+    end
+
     def parse_macro_expression
       next_token_skip_space_or_newline
       parse_expression_inside_macro
@@ -2705,6 +2702,17 @@ module Crystal
       check :"}"
     end
 
+    def parse_percent_macro_control
+      macro_control = parse_macro_control(@line_number, @column_number)
+      if macro_control
+        check :"%}"
+        next_token_skip_space
+        macro_control
+      else
+        unexpected_token_in_atomic
+      end
+    end
+
     def parse_macro_control(start_line, start_column, macro_state = Token::MacroState.default)
       next_token_skip_space_or_newline
 
@@ -3405,9 +3413,9 @@ module Crystal
     def parse_ifdef_body(mode)
       case mode
       when :lib
-        parse_lib_body
+        parse_lib_body_expressions
       when :struct_or_union
-        parse_struct_or_union_body
+        parse_struct_or_union_body_expressions
       else
         parse_expressions
       end
@@ -4553,7 +4561,7 @@ module Crystal
       name_column_number = @token.column_number
       next_token_skip_statement_end
 
-      body = parse_lib_body
+      body = parse_lib_body_expressions
 
       check_ident :end
       next_token_skip_space
@@ -4562,6 +4570,11 @@ module Crystal
     end
 
     def parse_lib_body
+      next_token_skip_statement_end
+      Expressions.from(parse_lib_body_expressions)
+    end
+
+    private def parse_lib_body_expressions
       expressions = [] of ASTNode
       while true
         skip_statement_end
@@ -4630,6 +4643,10 @@ module Crystal
 
         skip_statement_end
         ExternalVar.new(name, type, real_name)
+      when :"{{"
+        parse_percent_macro_expression
+      when :"{%"
+        parse_percent_macro_control
       else
         unexpected_token
       end
@@ -4813,14 +4830,19 @@ module Crystal
       next_token_skip_space_or_newline
       name = check_const
       next_token_skip_statement_end
-      body = parse_struct_or_union_body
+      body = parse_struct_or_union_body_expressions
       check_ident :end
       next_token_skip_space
 
       klass.new name, Expressions.from(body)
     end
 
     def parse_struct_or_union_body
+      next_token_skip_statement_end
+      Expressions.from(parse_struct_or_union_body_expressions)
+    end
+
+    private def parse_struct_or_union_body_expressions
       exps = [] of ASTNode
 
       while true
@@ -4843,6 +4865,10 @@ module Crystal
           else
             parse_struct_or_union_fields exps
           end
+        when :"{{"
+          exps << parse_percent_macro_expression
+        when :"{%"
+          exps << parse_percent_macro_control
         when :";", :NEWLINE
           skip_statement_end
         else