Implement elsif

gcc/elna-generic.cc

@@ -733,70 +733,62 @@ namespace gcc
 
     void generic_visitor::visit(source::if_statement *statement)
     {
-        statement->body().prerequisite().accept(this);
+        tree endif_label_decl = build_label_decl("endif", UNKNOWN_LOCATION);
+        tree goto_endif = build1(GOTO_EXPR, void_type_node, endif_label_decl);
 
-        if (TREE_TYPE(this->current_expression) != boolean_type_node)
+        make_if_branch(statement->body(), goto_endif);
+
+        for (const auto branch : statement->branches)
         {
-            error_at(get_location(&statement->body().prerequisite().position()),
+            make_if_branch(*branch, goto_endif);
-                    "expected expression of boolean type but its type is %s",
-                    print_type(TREE_TYPE(this->current_expression)));
-            this->current_expression = error_mark_node;
-            return;
-        }
-        auto then_location = get_location(&statement->position());
-        auto prerequisite_location = get_location(&statement->body().prerequisite().position());
-
-        auto then_label_decl = build_label_decl("then", then_location);
-        auto endif_label_decl = build_label_decl("end_if", then_location);
-
-        auto goto_then = build1_loc(prerequisite_location, GOTO_EXPR,
-                void_type_node, then_label_decl);
-        auto goto_endif = build1_loc(prerequisite_location, GOTO_EXPR,
-                void_type_node, endif_label_decl);
-
-        tree else_label_decl = NULL_TREE;
-        tree goto_else_or_endif = NULL_TREE;
-        if (statement->alternative() != nullptr)
-        {
-            auto else_location = get_location(&statement->position());
-            else_label_decl = build_label_decl("else", else_location);
-            goto_else_or_endif = build1_loc(else_location, GOTO_EXPR, void_type_node, else_label_decl);
-        }
-        else
-        {
-            goto_else_or_endif = goto_endif;
-        }
-
-        auto cond_expr = build3_loc(prerequisite_location, COND_EXPR,
-                void_type_node, this->current_expression, goto_then, goto_else_or_endif);
-        append_to_statement_list(cond_expr, &this->current_statements);
-
-        auto then_label_expr = build1_loc(then_location, LABEL_EXPR,
-                void_type_node, then_label_decl);
-        append_to_statement_list(then_label_expr, &this->current_statements);
-
-        for (const auto body_statement : statement->body().statements)
-        {
-            body_statement->accept(this);
         }
         if (statement->alternative() != nullptr)
         {
-            append_to_statement_list(goto_endif, &this->current_statements);
-
-            auto else_label_expr = build1(LABEL_EXPR, void_type_node, else_label_decl);
-            append_to_statement_list(else_label_expr, &this->current_statements);
-
             for (const auto body_statement : *statement->alternative())
             {
                 body_statement->accept(this);
             }
         }
-        auto endif_label_expr = build1(LABEL_EXPR, void_type_node, endif_label_decl);
-        append_to_statement_list(endif_label_expr, &this->current_statements);
 
+        tree endif_label_expr = build1(LABEL_EXPR, void_type_node, endif_label_decl);
+        append_to_statement_list(endif_label_expr, &this->current_statements);
         this->current_expression = NULL_TREE;
     }
 
+    void generic_visitor::make_if_branch(source::conditional_statements& branch, tree goto_endif)
+    {
+        branch.prerequisite().accept(this);
+
+        if (TREE_TYPE(this->current_expression) != boolean_type_node)
+        {
+            error_at(get_location(&branch.prerequisite().position()),
+                    "expected expression of boolean type but its type is %s",
+                    print_type(TREE_TYPE(this->current_expression)));
+            this->current_expression = error_mark_node;
+            return;
+        }
+        tree then_label_decl = build_label_decl("then", UNKNOWN_LOCATION);
+        tree goto_then = build1(GOTO_EXPR, void_type_node, then_label_decl);
+
+        tree else_label_decl = build_label_decl("else", UNKNOWN_LOCATION);
+        tree goto_else = build1(GOTO_EXPR, void_type_node, else_label_decl);
+
+        auto cond_expr = build3(COND_EXPR, void_type_node, this->current_expression, goto_then, goto_else);
+        append_to_statement_list(cond_expr, &this->current_statements);
+
+        tree then_label_expr = build1(LABEL_EXPR, void_type_node, then_label_decl);
+        append_to_statement_list(then_label_expr, &this->current_statements);
+
+        for (const auto body_statement : branch.statements)
+        {
+            body_statement->accept(this);
+        }
+        append_to_statement_list(goto_endif, &this->current_statements);
+
+        tree else_label_expr = build1(LABEL_EXPR, void_type_node, else_label_decl);
+        append_to_statement_list(else_label_expr, &this->current_statements);
+    }
+
     tree generic_visitor::build_label_decl(const char *name, location_t loc)
     {
         auto label_decl = build_decl(loc,

include/elna/gcc/elna-generic.h

@@ -34,6 +34,8 @@ namespace gcc
         void build_binary_operation(bool condition, source::binary_expression *expression,
             tree_code operator_code, tree left, tree right, tree target_type);
 
+        void make_if_branch(source::conditional_statements& branch, tree goto_endif);
+
     public:
         generic_visitor(std::shared_ptr<source::symbol_table<tree>> symbol_table);
 

include/elna/source/ast.h

@@ -617,6 +617,8 @@ namespace source
         std::vector<statement *> *m_alternative;
 
     public:
+        std::vector<conditional_statements *> branches;
+
         if_statement(const struct position position, conditional_statements *body,
                 std::vector<statement *> *alternative = nullptr);
         virtual void accept(parser_visitor *visitor) override;

source/ast.cc

@@ -898,7 +898,10 @@ namespace source
     if_statement::~if_statement()
     {
         delete m_body;
-
+        for (const auto branch : branches)
+        {
+            delete branch;
+        }
         if (m_alternative != nullptr)
         {
             delete m_alternative;

source/parser.yy

@@ -96,6 +96,7 @@
 %type <elna::source::block *> block;
 %type <std::pair<std::string, elna::source::type_expression *>> field_declaration;
 %type <std::vector<std::pair<std::string, elna::source::type_expression *>>> field_list;
+%type <std::vector<elna::source::conditional_statements *>> elsif_statement_list;
 %%
 program:
     type_part constant_part procedure_part variable_part BEGIN_BLOCK optional_statements END_BLOCK DOT
@@ -121,7 +122,7 @@ program:
             {
                 *value_definition++ = variable;
             }
-            auto tree = new elna::source::program(elna::source::position{},
+            auto tree = new elna::source::program(elna::source::make_position(@5),
                  std::move(definitions), std::move(value_definitions), std::move($6));
 
             driver.tree.reset(tree);
@@ -139,28 +140,28 @@ block: constant_part variable_part BEGIN_BLOCK optional_statements END_BLOCK
             {
                 *definition++ = variable;
             }
-            $$ = new elna::source::block(elna::source::position{},
+            $$ = new elna::source::block(elna::source::make_position(@3),
                  std::move(definitions), std::move($4));
         }
 procedure_definition:
     PROCEDURE IDENTIFIER formal_parameter_list SEMICOLON block SEMICOLON
         {
-            $$ = new elna::source::procedure_definition(elna::source::position{},
+            $$ = new elna::source::procedure_definition(elna::source::make_position(@1),
                  $2, std::move($3), nullptr, $5);
         }
     | PROCEDURE IDENTIFIER formal_parameter_list SEMICOLON EXTERN SEMICOLON
         {
-            $$ = new elna::source::procedure_definition(elna::source::position{},
+            $$ = new elna::source::procedure_definition(elna::source::make_position(@1),
                  $2, std::move($3), nullptr, nullptr);
         }
     | PROCEDURE IDENTIFIER formal_parameter_list COLON type_expression SEMICOLON block SEMICOLON
         {
-            $$ = new elna::source::procedure_definition(elna::source::position{},
+            $$ = new elna::source::procedure_definition(elna::source::make_position(@1),
                  $2, std::move($3), $5, $7);
         }
     | PROCEDURE IDENTIFIER formal_parameter_list COLON type_expression SEMICOLON EXTERN SEMICOLON
         {
-            $$ = new elna::source::procedure_definition(elna::source::position{},
+            $$ = new elna::source::procedure_definition(elna::source::make_position(@1),
                  $2, std::move($3), $5, nullptr);
         }
 procedure_definitions:
@@ -188,19 +189,30 @@ while_statement: WHILE expression DO optional_statements END_BLOCK
             std::swap($4, body->statements);
             $$ = new elna::source::while_statement(elna::source::make_position(@1), body);
         }
+elsif_statement_list:
+    ELSIF expression THEN optional_statements elsif_statement_list
+        {
+            elna::source::conditional_statements *branch = new elna::source::conditional_statements($2);
+            std::swap(branch->statements, $4);
+            std::swap($5, $$);
+            $$.emplace($$.begin(), branch);
+        }
+    | {}
 if_statement:
-    IF expression THEN optional_statements END_BLOCK
+    IF expression THEN optional_statements elsif_statement_list END_BLOCK
         {
             auto then = new elna::source::conditional_statements($2);
             std::swap($4, then->statements);
             $$ = new elna::source::if_statement(elna::source::make_position(@1), then);
+            std::swap($5, $$->branches);
         }
-    | IF expression THEN optional_statements ELSE optional_statements END_BLOCK
+    | IF expression THEN optional_statements elsif_statement_list ELSE optional_statements END_BLOCK
         {
             auto then = new elna::source::conditional_statements($2);
             std::swap($4, then->statements);
-            auto _else = new std::vector<elna::source::statement *>(std::move($6));
+            auto _else = new std::vector<elna::source::statement *>(std::move($7));
             $$ = new elna::source::if_statement(elna::source::make_position(@1), then, _else);
+            std::swap($5, $$->branches);
         }
 return_statement:
     RETURN expression