Implement for loop

1 files changed, 29 insertions, 26 deletions

diff --git a/boot/parser.yy b/boot/parser.yy
index bc2ddb5..7d93dde 100644
--- a/boot/parser.yy
+++ b/boot/parser.yy
@@ -99,12 +99,8 @@ along with GCC; see the file COPYING3.  If not see
     TYPE "type"
     RECORD "record"
     EXTERN "extern"
-    IF "if"
-    WHILE "while"
-    DO "do"
-    THEN "then"
-    ELSE "else"
-    ELSIF "elsif"
+    IF "if" THEN "then" ELSE "else" ELSIF "elsif"
+    WHILE "while" DO "do" FOR "for" BY "by"
     RETURN "return"
     IMPORT "import"
     BEGIN_BLOCK "begin"
@@ -135,7 +131,7 @@ along with GCC; see the file COPYING3.  If not see
 %type <elna::boot::type_expression *> type_expression;
 %type <std::vector<elna::boot::type_expression *>> type_expressions;
 %type <elna::boot::traits_expression *> traits_expression;
-%type <elna::boot::expression *> expression operand simple_expression procedure_return;
+%type <elna::boot::expression *> expression operand simple_expression procedure_return by_step;
 %type <elna::boot::unary_expression *> unary_expression;
 %type <elna::boot::binary_expression *> binary_expression;
 %type <std::vector<elna::boot::expression *>> expressions actual_parameter_list;
@@ -156,7 +152,6 @@ along with GCC; see the file COPYING3.  If not see
 %type <std::vector<elna::boot::field_initializer>> field_initializers;
 %type <std::vector<elna::boot::conditional_statements *>> elsif_then_statements elsif_do_statements;
 %type <std::vector<elna::boot::statement *> *> else_statements;
-%type <elna::boot::cast_expression *> cast_expression;
 %type <std::unique_ptr<elna::boot::identifier>> identifier;
 %type <std::unique_ptr<elna::boot::identifier_definition>> identifier_definition;
 %type <std::vector<elna::boot::identifier_definition>> identifier_definitions;
@@ -175,7 +170,7 @@ procedure_body:
         { $$ = std::make_unique<boot::procedure_body>($1, $2, $3); }
 
 statement_part:
-    /* no statements */ {}
+    %empty {}
     | "begin" statements { $$ = $2; }
 identifier:
     IDENTIFIER { $$ = std::make_unique<boot::identifier>($1, boot::make_position(@1)); }
@@ -190,7 +185,7 @@ identifier_definitions:
         }
     | identifier_definition { $$.emplace_back(std::move(*$1)); }
 return_declaration:
-    /* proper procedure */ {}
+    %empty {}
     | ":" "!" { $$ = boot::procedure_type_expression::return_t(std::monostate{}); }
     | ":" type_expression { $$ = boot::procedure_type_expression::return_t($2); }
 procedure_heading: "(" optional_fields ")" return_declaration
@@ -205,7 +200,7 @@ procedure_declaration:
             $$ = new boot::procedure_declaration(boot::make_position(@$), std::move(*$2), $3);
         }
 procedure_part:
-    /* no procedure declarations */ {}
+    %empty {}
     | procedure_declaration procedure_part
         {
             $$ = $2;
@@ -215,8 +210,9 @@ call_expression: designator_expression actual_parameter_list
         {
             $$ = new boot::procedure_call(boot::make_position(@$), $1, $2);
         }
-cast_expression: "cast" "(" expression ":" type_expression ")"
-        { $$ = new boot::cast_expression(boot::make_position(@$), $5, $3); }
+by_step:
+    "by" expression { $$ = $2; }
+    | %empty { $$ = nullptr; }
 elsif_do_statements:
     "elsif" expression "do" statements elsif_do_statements
         {
@@ -224,10 +220,10 @@ elsif_do_statements:
             $$ = $5;
             $$.emplace($$.begin(), branch);
         }
-    | /* no branches */ {}
+    | %empty {}
 else_statements:
     "else" statements { $$ = new std::vector<boot::statement *>($2); }
-    | { $$ = nullptr; }
+    | %empty { $$ = nullptr; }
 elsif_then_statements:
     "elsif" expression "then" statements elsif_then_statements
         {
@@ -235,7 +231,7 @@ elsif_then_statements:
             $$ = $5;
             $$.emplace($$.begin(), branch);
         }
-    | /* no branches */ {}
+    | %empty {}
 procedure_return:
     "return" expression { $$ = $2; }
     | "return" { $$ = nullptr; }
@@ -257,7 +253,10 @@ simple_expression:
     literal { $$ = $1; }
     | designator_expression { $$ = $1; }
     | traits_expression { $$ = $1; }
-    | cast_expression { $$ = $1; }
+    | "cast" "(" expression ":" type_expression ")"
+        {
+            $$ = new boot::cast_expression(boot::make_position(@$), $5, $3);
+        }
     | call_expression { $$ = $1; }
     | "(" expression ")" { $$ = $2; }
     | identifier "{" field_initializers "}"
@@ -363,6 +362,7 @@ expressions:
             $$.emplace($$.cbegin(), $1);
         }
     | expression { $$.push_back($1); }
+    | %empty { $$ = std::vector<elna::boot::expression *>(); }
 type_expressions:
     type_expression "," type_expressions
         {
@@ -389,6 +389,10 @@ statement:
             boot::conditional_statements *body = new boot::conditional_statements($2, $4);
             $$ = new boot::while_statement(boot::make_position(@$), body, $5);
         }
+    | "for" identifier ":=" expression "to" expression by_step "do" statements "end"
+        {
+            $$ = new boot::for_statement(boot::make_position(@$), std::move(*$2), $4, $6, $9, $7);
+        }
     | "if" expression "then" statements elsif_then_statements else_statements "end"
         {
             boot::conditional_statements *then = new boot::conditional_statements($2, $4);
@@ -399,7 +403,7 @@ statement:
         { $$ = new boot::defer_statement(boot::make_position(@$), $2); }
     | "case" expression "of" switch_cases else_statements "end"
         { $$ = new boot::case_statement(boot::make_position(@$), $2, $4, $5); }
-	| { $$ = new boot::empty_statement(boot::make_position(@$)); }
+    | %empty { $$ = new boot::empty_statement(boot::make_position(@$)); }
 switch_case: case_labels ":" statements
         { $$ = { .labels = $1, .statements = $3 }; }
 switch_cases:
@@ -434,7 +438,7 @@ required_fields:
     | field_declaration { $$.emplace_back($1); }
 optional_fields:
     required_fields { $$ = $1; }
-    | /* no fields */ {}
+    | %empty {}
 field_initializer:
     identifier ":" expression { $$ = std::make_unique<boot::field_initializer>(std::move(*$1), $3); }
 field_initializers:
@@ -505,14 +509,14 @@ variable_declaration:
             $$ = new boot::variable_declaration( boot::make_position(@$), $1, shared_type, $5);
         }
 variable_declarations:
-    /* no variable declarations */ {}
+    %empty {}
     | variable_declaration variable_declarations
         {
             $$ = $2;
             $$.insert(std::cbegin($$), $1);
         }
 variable_part:
-    /* no variable declarations */ {}
+    %empty {}
     | "var" variable_declarations { $$ = $2; }
 import_declaration:
     IDENTIFIER "." import_declaration
@@ -532,7 +536,7 @@ import_declarations:
             $$.emplace_back(new boot::import_declaration(boot::make_position(@$), $1));
         }
 import_part:
-    /* no import declarations */ {}
+    %empty {}
     | "import" import_declarations { $$ = $2; }
 type_declaration: identifier_definition "=" type_expression
         {
@@ -544,13 +548,12 @@ type_declarations:
             $$ = $2;
             $$.insert($$.cbegin(), $1);
         }
-    | /* no type definitions */ {}
+    | %empty {}
 type_part:
-    /* no type definitions */ {}
+    %empty {}
     | "type" type_declarations { $$ = $2; }
 actual_parameter_list:
-    "(" ")" {}
-    | "(" expressions ")" { $$ = $2; }
+    "(" expressions ")" { $$ = $2; }
 %%
 
 void yy::parser::error(const location_type& loc, const std::string& message)