Tcl

Call a JavaScript Function Returning a String

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Demonstrates how to call a JavaScript function that returns a string. Tcl

load ./chilkat.dll

set success 0

# This is the JavaScript function we'll call:

# function greet(name) {
#     return "Hello, " + name + "!";
# }

set sbScript [new_CkStringBuilder]

CkStringBuilder_Append $sbScript "function greet(name) { return \"Hello, \" + name + \"!\"; }"

set js [new_CkJs]

set result [new_CkJsonObject]

CkJsonObject_put_EmitCompact $result 0

# Call Eval to add the function to the context's global object
set success [CkJs_Eval $js $sbScript $result]
if {$success == 0} then {
    # Examine the result for an exception.
    puts [CkJsonObject_emit $result]

    # Also examine the LastErrorText.
    puts [CkJs_lastErrorText $js]
    delete_CkStringBuilder $sbScript
    delete_CkJs $js
    delete_CkJsonObject $result
    exit
}

# ------------------------------------------------------------------------------
# Call the function greet("Michael")

set funcCall [new_CkJsonObject]

# Create JSON specifying the function name and arguments

# {
#   "name": "greet",
#   "args": [ "Michael" ]
# }

CkJsonObject_UpdateString $funcCall "name" "greet"
CkJsonObject_UpdateString $funcCall "args[0]" "Michael"

set success [CkJs_CallFunction $js $funcCall $result]
if {$success == 0} then {
    # Examine the result for an exception.
    puts [CkJsonObject_emit $result]

    # Also examine the LastErrorText.
    puts [CkJs_lastErrorText $js]
    delete_CkStringBuilder $sbScript
    delete_CkJs $js
    delete_CkJsonObject $result
    delete_CkJsonObject $funcCall
    exit
}

puts [CkJsonObject_emit $result]

# Output:
# {
#   "type": "string",
#   "value": "Hello, Michael!"
# }

set retval [CkJsonObject_stringOf $result "value"]
puts "$retval"

# Output:
# Hello, Michael!

delete_CkStringBuilder $sbScript
delete_CkJs $js
delete_CkJsonObject $result
delete_CkJsonObject $funcCall