---
name: "critcl_enum"
section: "3tcl"
platform: "linux"
package: "critcl"
version: "3.3.1+dfsg-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/critcl_enum"
---

# critcl\_enum(3tcl)

CriTcl - Wrap Support - String/Integer mapping

```

```

## NAME

critcl::enum - CriTcl - Wrap Support - String/Integer mapping

## SYNOPSIS

package require **Tcl  8.6**

package require **critcl  ?3.2?**

package require **critcl::enum  ?1.2?**

**::critcl::enum::def** *name* *definition* ?*mode*?

```

```

## DESCRIPTION

Be welcome to the *C Runtime In Tcl* (short: *CriTcl*), a system for embedding and using C code from within *Tcl* \[http://core.tcl-lang.org/tcl\] scripts.

This document is the reference manpage for the **critcl::enum** package. This package provides convenience commands for advanced functionality built on top of both critcl core and package **critcl::literals**.

It is an extended form of string pool which not only converts integer values into Tcl-level strings, but also handles the reverse direction, converting from strings to the associated integer values.

It essentially provides a bi-directional mapping between a C enumeration type and a set of strings, one per enumeration value. *Note* that the C enumeration in question is created by the definition. It is not possible to use the symbols of an existing enumeration type.

This package was written to make the declaration and management of such mappings easy. It uses a string pool for one of the directions, using its ability to return shared literals and conserve memory.

Its intended audience are mainly developers wishing to write Tcl packages with embedded C code.

This package resides in the Core Package Layer of CriTcl.

```
+----------------+
|Applications    |
| critcl         |
| critcl::app    |
+----------------+
*================*
|Core Packages   |
| critcl         |
| critcl::util   |
*================*
+----------------+
|Support Packages|
| stubs::*       |
| md5, platform  |
|  ...           |
+----------------+
```

## API

- **::critcl::enum::def** *name* *definition* ?*mode*?

  This command defines two C functions for the conversion between C values and Tcl\_Obj'ects, with named derived from *name*.

  The *definition* dictionary provides the mapping from the specified C-level symbolic names to the strings themselves.

  The *mode*-list configures the output somewhat. The two allowed modes are **+list** and **tcl**. All modes can be used together. The default mode is **tcl**. Using mode **+list** implies **tcl** as well.

  For mode **tcl** the new function has two arguments, a **Tcl\_Interp\*** pointer refering to the interpreter holding the string pool, and a code of type "*name*\_pool\_names" (see below), the symbolic name of the string to return. The result of the function is a **Tcl\_Obj\*** pointer to the requested string constant.

  For mode **+list** all of **tcl** applies, plus an additional function is generated which takes three arguments, in order: a **Tcl\_Interp\*** pointer refering to the interpreter holding the string pool, an **int** holding the size of the last argument, and an array of type "*name*\_pool\_names" holding the codes (see below), the symbolic names of the strings to return. The result of the function is a **Tcl\_Obj\*** pointer to a Tcl list holding the requested string constants.

  The underlying string pool is automatically initialized on first access, and finalized on interpreter destruction.

  The package generates multiple things (declarations and definitions) with names derived from *name*, which has to be a proper C identifier.

  - *name*\_pool\_names

    The C enumeration type containing the specified symbolic names.

  - *name*\_ToObj

    The function converting from integer value to Tcl string. Its signature is

    ```
    Tcl_Obj* name_ToObj (Tcl_Interp* interp, name_names literal);
    ```

  - *name*\_ToObjList

    The mode **+list** function converting from integer array to Tcl list of strings. Its signature is

    ```
    Tcl_Obj* name_ToObjList (Tcl_Interp* interp, int c, name_names* literal);
    ```

  - *name*\_GetFromObj

    The function converting from Tcl string to integer value. Its signature is

    ```
    int name_GetFromObj (Tcl_Interp* interp, Tcl_Obj* obj, int flags, int* literal);
    ```

  -

    The *flags* are like for **Tcl\_GetIndexFromObj**.

  - *name*.h

    A header file containing the declarations for the converter functions, for use by other parts of the system, if necessary.

    The generated file is stored in a place where it will not interfere with the overall system outside of the package, yet also be available for easy inclusion by package files (**csources**).

  - *name*

    At the level of critcl itself the command registers a new result-type for **critcl::cproc**, which takes an integer result from the function and converts it to the equivalent string in the pool for the script.

  - *name*

    At the level of critcl itself the command registers a new argument-type for **critcl::cproc**, which takes a Tcl string and converts it to the equivalent integer for delivery to the function.

## EXAMPLE

The example shown below is the specification for a set of actions, methods, and the like, a function may take as argument.

```
package require Tcl 8.6
package require critcl 3.2
critcl::buildrequirement {
    package require critcl::enum
}
critcl::enum::def action {
    w_create	"create"
    w_directory	"directory"
    w_events	"events"
    w_file	"file"
    w_handler	"handler"
    w_remove	"remove"
}
# Declarations: action.h
# Type:         action_names
# Accessor:     Tcl_Obj* action_ToObj (Tcl_Interp* interp, int literal);
# Accessor:     int action_GetFromObj (Tcl_Interp* interp, Tcl_Obj* o, int flags, int* literal);
# ResultType:   action
# ArgType:      action
```

## AUTHORS

Andreas Kupries

## BUGS, IDEAS, FEEDBACK

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such at *https://github.com/andreas-kupries/critcl*. Please also report any ideas for enhancements you may have for either package and/or documentation.

## KEYWORDS

C code, Embedded C Code, Tcl Interp Association, code generator, compile & run, compiler, conversion, dynamic code generation, dynamic compilation, generate package, int to string mapping, linker, literal pool, on demand compilation, on-the-fly compilation, singleton, string pool, string to int mapping

## CATEGORY

Glueing/Embedded C code

## COPYRIGHT

```
Copyright (c) 2011-2024 Andreas Kupries
```