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Tcl

This structure connects the Tcl system to OPAL.

Signature of Tcl

List of Import References :
See BOOL
See BTUnion
See Char
See Com
See DENOTATION
See Int
See Nat
See Option
See Real
See Seq
See String
See Void

SIGNATURE Tcl[state:SORT]

$Date: 2010-09-30 18:24:17 +0200 (Do, 30. Sep 2010) $ ($Revision: 616 $)

-- Version $_version$

IMPORT  Nat                     ONLY nat
        Int                     ONLY int
        Real                    ONLY real
        String                  ONLY string
        BTUnion                 ONLY union
        Void                    ONLY void
        Seq[string]             ONLY seq
        Seq[union]              ONLY seq
        Com[bool]               ONLY ans:SORT 
        Com[nat]                ONLY ans:SORT 
        Com[int]                ONLY ans:SORT 
        Com[real]               ONLY ans:SORT 
        Com[void]               ONLY com 
        Com[string]             ONLY com ans:SORT
        Com[seq[string]]        ONLY ans:SORT
        Com[interpreter]        ONLY com
        Com[state]              ONLY com

Access to Tcl is realized by providing Tcl interpreters as first-class OPAL values. Each such interpreter carries an abstract state of the parameter sort of this structure. A new interpreter is created from the initial value of the state. To free the resources allocated by an interpreter, the function delete must be used.

SORT interpreter                

SORT state              
                
FUN create      : state                 -> com[interpreter]
FUN delete      : interpreter           -> com[void]

The state embedded in a interpreter is retrieved and changed by the following functions:

FUN  state      : interpreter                           -> com[state]
FUN  =>         : interpreter ** (state -> state)       -> com[void]

Defining New Commands

A new Tcl command, implemented in OPAL, is defined for a given interpreter with the functions below. The first form uses a pure function, the second form an OPAL command monad to define the behavior of the Tcl command.

FUN define      : interpreter ** denotation 
                     ** (interpreter ** seq[string] -> ans[string]) 
                     -> com[void]
FUN define      : interpreter ** denotation 
                     ** (interpreter ** seq[string] -> com[string]) 
                     -> com[void]

If the command is called from within Tcl, the first argument is the interpreter executing it. The second argument is a sequence of strings, in which the first element always represents the name of the command and the remaining elements the arguments to the command.

NB. During the execution of an OPAL-implemented Tcl command, agent scheduling does not takes place. This implies that no agent communcation is possible. It is, however, possible to spawn an agent from within the execution of the Tcl command, which will start its activity after control is returned to the OPAL program.

The following function undefines a command in the given Tcl interpreter:

FUN undefine    : interpreter ** denotation             -> com[void]

Evaluating Scripts

Several functions are provided to evaluate Tcl scripts. The form which uses a seq[union] constructs the script on the base of the format'StringFormat facility.

FUN @   : interpreter ** denotation                     -> com[string]
FUN @   : interpreter ** denotation ** seq[union]       -> com[string]
FUN @   : interpreter ** string                         -> com[string]
FUN @   : interpreter ** seq[string]                    -> com[string]

To evaluate the contents of a named file as a Tcl script, use the function source:

FUN source : interpreter ** denotation                  -> com[string]

Converting Tcl Data

The functions below convert Tcl data values into OPAL data values:

FUN asNat       : string                                -> ans[nat]
FUN asInt       : string                                -> ans[int]
FUN asBool      : string                                -> ans[bool]
FUN asReal      : string                                -> ans[real]
FUN asList      : string                                -> ans[seq[string]]

The function asString takes a sequence and converts it into a string, which represents a properly quoted Tcl list.

FUN asString    : seq[string]                           -> string

The function commandComplete tests whether the given string is a complete Tcl command w.r.t. the balancing of brackets.

FUN commandComplete? : string                           -> bool

Accessing Tcl Variables

To read from Tcl variables, use the functions below. The forms with two denotations specify an array element. The forms with a dot refer to global variables.

FUN !   : interpreter ** denotation                     -> com[string]
FUN !   : interpreter ** denotation ** denotation       -> com[string]
FUN .!  : interpreter ** denotation                     -> com[string]
FUN .!  : interpreter ** denotation ** denotation       -> com[string]

Similar as for reading, variable values may be assigned with the following functions.

FUN :=  : interpreter ** denotation               ** string     -> com[void]
FUN :=  : interpreter ** denotation ** denotation ** string     -> com[void]
FUN .:= : interpreter ** denotation               ** string     -> com[void]
FUN .:= : interpreter ** denotation ** denotation ** string     -> com[void]