#200 - update grammar and lex regex

Author: Stepami

src/Domain/HydraScript.Domain.Constants/TokenTypes.cs

@@ -63,14 +63,19 @@ public static IEnumerable<Dto> Stream
                 Priority: 11);
 
             yield return new(
-                Tag: "Print",
+                Tag: "Output",
                 Pattern: "[>]{3}",
                 Priority: 12);
 
+            yield return new(
+                Tag: "Input",
+                Pattern: "[<]{3}",
+                Priority: 13);
+
             yield return new(
                 Tag: "Operator",
                 Pattern: "[+]{1,2}|[-]|[*]|[/]|[%]|([!]|[=])[=]|([<]|[>])[=]?|[!]|[|]{2}|[&]{2}|[~]|[:]{2}|[$]",
-                Priority: 13);
+                Priority: 14);
 
             yield return new(
                 Tag: "Comma",

src/Domain/HydraScript.Domain.FrontEnd/Parser/grammar.txt

@@ -11,6 +11,7 @@ Statement -> BlockStatement
              BreakStatement
              ReturnStatement
              OutputStatement
+             InputStatement
 
 Declaration -> LexicalDeclaration
                FunctionDeclaration
@@ -68,6 +69,7 @@ BreakStatement -> 'break'
 ReturnStatement -> 'return' Expression?
 
 OutputStatement -> '>>>' Expression
+InputStatement -> '<<<' (Ident | EnvVar)
 
 TypeDeclaration -> 'type' "Ident" = TypeValue
 TypeValue -> TypeValueBase TypeValueSuffix*