Script : /* empty */
       | Decls
       ;

Decls : Decl
      | Decls Decl
      ;

Decl : Import
     | "type" TypeDecls ";"
     | "tool" IDENTIFIERTK OptTypeParams ToolParameters ":" OptStatements "end"
     | "tool" Types IDENTIFIERTK OptTypeParams ToolParameters ":" OptStatements "end"
     | Statement
     ;

Import : "import" STRINGTK ";"
       | "import" STRINGTK "as" IDENTIFIERTK ";"
       | "import" Name ";"
       | "import" Name "as" IDENTIFIERTK ";"
       | "import" Name ":" Name ";"
       | "import" Name ":" Name "as" IDENTIFIERTK ";"
       | "from" STRINGTK "import" ImportParts ";"
       ;

ImportParts : "*"
            | IDENTIFIERTK
            | IDENTIFIERTK "as" IDENTIFIERTK
            | ImportParts "," "*"
            | ImportParts "," IDENTIFIERTK
            | ImportParts "," IDENTIFIERTK "as" IDENTIFIERTK
            ;

TypeDecls : TypeDecl
          | TypeDecls "," TypeDecl
          ;

TypeDecl : IDENTIFIERTK "=" Type
         ;

OptTypeParams : /* empty */
              | "<" Names ">"
              ;

ToolParameters : "(" ")"
               | "(" ToolParams ")"
               ;

ToolParams : Type ToolParam
           | Type "..." ToolParam
           | ToolParams "," Type ToolParam
           | ToolParams "," Type "..." ToolParam
           ;

ToolParam : IDENTIFIERTK
          | IDENTIFIERTK "=" Expression
          ;

OptStatements : /* empty */
              | OptStatements Statement
              ;

Statement : Type VarDecls ";"
          | "while" Expression ":" OptStatements "end"
          | "while" Expression "::" Statement
          | "for" AddressableDecls "in" Expression ":" OptStatements "end"
          | "for" AddressableDecls "in" Expression "::" Statement
          | "if" Expression ":" OptStatements OptElifStatements OptElseStatement "end"
          | "if" Expression "::" Statement
          | "break" ";"
          | "continue" ";"
          | Addressables "=" Expressions ";"
          | "return" ";"
          | "return" Expressions ";"
          | ToolInvokeExpression ";"
          | "exit" ";"
          | "exit" Expression ";"
          ;

VarDecls : VarDecl
         | VarDecls "," VarDecl
         ;

VarDecl : IDENTIFIERTK
        | IDENTIFIERTK "=" Expression
        ;

OptElifStatements : /* empty */
                  | OptElifStatements "elif" Expression ":" OptStatements
                  ;

OptElseStatement : /* empty */
                 | "else" OptStatements
                 ;

AddressableDecls : AddressableDecl
                 | AddressableDecls "," AddressableDecl
                 ;

AddressableDecl : IDENTIFIERTK
                | "(" AddressableDecl "," AddressableDecls ")"
                ;

Addressables : Addressable
             | Addressables "," Addressable
             ;

Addressable : IDENTIFIERTK
            | IDENTIFIERTK Projections
            | "(" Addressable "," Addressables ")"
            ;

Projections : Projection
            | Projections Projection
            ;

Projection : "[" Expression "]"
           ;

Types : Type
      | Types "," Type
      ;

Type : "bool"
     | "bool" "?"
     | "int"
     | "int" "?"
     | "long"
     | "long" "?"
     | "double"
     | "double" "?"
     | "string"
     | "string" "?"
     | "list" Type
     | "list" "?" Type
     | "set" Type
     | "set" "?" Type
     | "map" "(" Type ":" Type ")"
     | "map" "?" "(" Type ":" Type ")"
     | "tuple" "(" Type "," Types ")"
     | "tuple" "?" "(" Type "," Types ")"
     | "object"
     | "object" "?"
     | Name
     ;

Expressions : Expression
            | Expressions "," Expression
            ;

OptExpression : /* empty */
              | Expression
              ;

Expression : AndExpression
           | Expression "or" AndExpression
           ;

AndExpression : CompareExpression
              | AndExpression "and" CompareExpression
              ;

CompareExpression : AddExpression
                  | CompareExpression "<" AddExpression
                  | CompareExpression "<=" AddExpression
                  | CompareExpression "==" AddExpression
                  | CompareExpression "!=" AddExpression
                  | CompareExpression ">=" AddExpression
                  | CompareExpression ">" AddExpression
                  ;

AddExpression : MulExpression
              | AddExpression "-" MulExpression
              | AddExpression "+" MulExpression
              ;

MulExpression : UnaryExpression
              | MulExpression "*" UnaryExpression
              | MulExpression "/" UnaryExpression
              | MulExpression "div" UnaryExpression
              | MulExpression "mod" UnaryExpression
              ;

UnaryExpression : ProjExpression
                | "-" UnaryExpression
                | "+" UnaryExpression
                | "not" UnaryExpression
                ;

ProjExpression : ExpressionFactor
               | ProjExpression "[" Expression "]"
               | ProjExpression "[" OptExpression ":" OptExpression "]"
               ;

ExpressionFactor : "true"
                 | "false"
                 | NUMBERTK
                 | DOUBLETK
                 | "null"
                 | STRINGTK
                 | "<" Type ">" ExpressionFactor
                 | "[" "]"
                 | "[" Expressions OptComma "]"
                 | "{" "}"
                 | "{" Expressions OptComma "}"
                 | "{" MapEntries OptComma "}"
                 | "(" Expression "," Expressions OptComma ")"
                 | "(" Expression ")"
                 | ToolInvokeExpression
                 | Name
                 ;

MapEntries : Expression ":" Expression
           | MapEntries "," Expression ":" Expression
           ;

ToolInvokeExpression : ToolRef "(" ToolArgs OptComma ")"
                     | ToolRef "(" ")"
                     ;

ToolRef : BuiltInTool
        | Name
        ;

BuiltInTool : BuiltInIoTool
            | BuiltInGenericTool
            | BuiltInPathTool
            | BuiltInFileTool
            | BuiltInDataTool
            ;

ToolArgs : Expression
         | IDENTIFIERTK "=" Expression
         | ToolArgs "," Expression
         | ToolArgs "," IDENTIFIERTK "=" Expression
         ;

Names : Name
      | Names "," Name
      ;

Name : IDENTIFIERTK
     | RELATIVENAMETK
     ;

OptComma : /* empty */
         | ","
         ;

BuiltInIoTool : "err"
              | "errln"
              | "out"
              | "outln"
              ;

BuiltInGenericTool : "app"
                   | "exec"
                   | "tooldef"
                   ;

BuiltInPathTool : "abspath"
                | "basename"
                | "chdir"
                | "chfileext"
                | "curdir"
                | "dirname"
                | "fileext"
                | "hasfileext"
                | "pathjoin"
                | "scriptpath"
                ;

BuiltInFileTool : "cpdir"
                | "cpfile"
                | "diff"
                | "exists"
                | "filenewer"
                | "filesize"
                | "find"
                | "isdir"
                | "isfile"
                | "mkdir"
                | "mvdir"
                | "mvfile"
                | "readlines"
                | "rmdir"
                | "rmfile"
                | "writefile"
                ;

BuiltInDataTool : "abs"
                | "ceil"
                | "contains"
                | "del"
                | "delidx"
                | "empty"
                | "endswith"
                | "entries"
                | "enumerate"
                | "floor"
                | "fmt"
                | "indexof"
                | "join"
                | "keys"
                | "lastindexof"
                | "ln"
                | "log"
                | "lower"
                | "ltrim"
                | "max"
                | "min"
                | "pow"
                | "range"
                | "replace"
                | "reverse"
                | "round"
                | "rtrim"
                | "size"
                | "sorted"
                | "split"
                | "sqrt"
                | "startswith"
                | "str"
                | "strdup"
                | "subset"
                | "trim"
                | "upper"
                | "values"
                ;