path: root/tests/unsupported.test

# Commands covered:  proc, apply, [interp alias], [namespce import], tailcall
#
# This file contains a collection of tests for experimental commands that are
# found in ::tcl::unsupported. The tests will migrate to normal test files
# if/when the commands find their way into the core.
#
# Copyright (c) 2008 by Miguel Sofer.
#
# See the file "license.terms" for information on usage and redistribution
# of this file, and for a DISCLAIMER OF ALL WARRANTIES.
#
# RCS: @(#) $Id: unsupported.test,v 1.1 2008/08/02 14:12:56 msofer Exp $

if {[lsearch [namespace children] ::tcltest] == -1} {
    package require tcltest
    namespace import -force ::tcltest::*
}

testConstraint testnrelevels [llength [info commands testnrelevels]]

#
# The tests that risked blowing the C stack on failure have been removed: we
# can now actually measure using testnrelevels.
#

if {[testConstraint testnrelevels]} {
    namespace eval testnre {
	#
	# [testnrelevels] returns a 6-list with: C-stack depth, iPtr->numlevels,
	# cmdFrame level, callFrame level, tosPtr and callback depth 
	#
	variable last [testnrelevels] 
	proc depthDiff {} {
	    variable last
	    set depth [testnrelevels]
	    set res {}
	    foreach t $depth l $last {
		lappend res [expr {$t-$l}]
	    }
	    set last $depth
	    return $res
	}
	proc setabs {} {
	    uplevel 1 variable abs -[lindex [testnrelevels] 0]
	}

	variable body0 {
	    set x [depthDiff]
	    if {[incr i] > 10} {
		variable abs
		incr abs [lindex [testnrelevels] 0]
		return [list [lrange $x 0 3] $abs]
	    }
	}
	proc makebody txt {
	    variable body0
	    return "$body0; $txt"
	}
	namespace export *
    }
    namespace import testnre::*
}

#
# Test tailcalls
#

testConstraint tailcall [llength [info commands ::tcl::unsupported::tailcall]]

if {[testConstraint tailcall]} {
    namespace eval tcl::unsupported namespace export tailcall
    namespace import tcl::unsupported::tailcall
}

test unsupported-T.0 {tailcall is constant space} -constraints {tailcall} -setup {
    proc a i {
	if {[incr i] > 10} {
	    return [depthDiff]
	}
	depthDiff
	tailcall a $i
    }
} -body {
    a 0
} -cleanup {
    rename a {}
} -result {0 0 0 0 0 0}

test unsupported-T.1 {tailcall} -constraints {tailcall} -body {
    namespace eval a {
	variable x *::a
	proc xset {} {
	    set tmp {}
	    set ns {[namespace current]}
	    set level [info level]
	    for {set i 0} {$i <= [info level]} {incr i} {
		uplevel #$i "set x $i$ns"
		lappend tmp "$i [info level $i]"
	    }
	    lrange $tmp 1 end
	}
	proc foo {} {tailcall xset; set x noreach}
    }
    namespace eval b {
	variable x *::b
	proc xset args {error b::xset}
	proc moo {} {set x 0; variable y [::a::foo]; set x}
    }
    variable x *::
    proc xset args {error ::xset}
    list [::b::moo] | $x $a::x $b::x | $::b::y 
} -cleanup {
    unset x
    rename xset {}
    namespace delete a b
} -result {1::b | 0:: *::a *::b | {{1 ::b::moo} {2 xset}}}


test unsupported-T.2 {tailcall in non-proc} -constraints {tailcall} -body {
    list [catch {namespace eval a [list tailcall set x 1]} msg] $msg
} -result {1 {tailcall can only be called from a proc or lambda}}

test unsupported-T.3 {tailcall falls off tebc} -constraints {tailcall} -body {
    unset -nocomplain x
    proc foo {} {tailcall set x 1}
    list [catch foo msg] $msg [set x]
} -cleanup {
    rename foo {}
    unset x
} -result {0 1 1}

test unsupported-T.4 {tailcall falls off tebc} -constraints {tailcall} -body {
    set x 2
    proc foo {} {tailcall set x 1}
    foo
    set x
} -cleanup {
    rename foo {}
    unset x
} -result 1

test unsupported-T.5 {tailcall falls off tebc} -constraints {tailcall} -body {
    set x 2
    namespace eval bar {
	variable x 3
	proc foo {} {tailcall set x 1}
    }
    bar::foo
    list $x $bar::x
} -cleanup {
    unset x
    namespace delete bar
} -result {1 3}

test unsupported-T.6 {tailcall does remove callframes} -constraints {tailcall} -body {
    proc foo {} {info level}
    proc moo {} {tailcall foo}
    proc boo {} {expr {[moo] - [info level]}}
    boo
} -cleanup {
    rename foo {}
    rename moo {}
    rename boo {}
} -result 1

test unsupported-T.7 {tailcall does return} -constraints {tailcall} -setup {
    namespace eval ::foo {
	variable res {}
	proc a {} {
	    variable res
	    append res a
	    tailcall set x 1
	    append res a
	}
	proc b {} {
	    variable res
	    append res b
	    a
	    append res b
	}
	proc c {} {
	    variable res
	    append res c
	    b
	    append res c
	}
    }
} -body {
    namespace eval ::foo c
} -cleanup {
    namespace delete ::foo
} -result cbabc

test unsupported-T.8 {tailcall tailcall} -constraints {tailcall} -setup {
    namespace eval ::foo {
	variable res {}
	proc a {} {
	    variable res
	    append res a
	    tailcall tailcall set x 1
	    append res a
	}
	proc b {} {
	    variable res
	    append res b
	    a
	    append res b
	}
	proc c {} {
	    variable res
	    append res c
	    b
	    append res c
	}
    }
} -body {
    namespace eval ::foo c
} -cleanup {
    namespace delete ::foo
} -match glob -result *tailcall* -returnCodes error

test unsupported-T.9 {tailcall factorial} -constraints {tailcall} -setup {
    proc fact {n {b 1}} {
	if {$n == 1} {
	    return $b
	}
	tailcall fact [expr {$n-1}] [expr {$n*$b}]
    }
} -body {
    list [fact 1] [fact 5] [fact 10] [fact 15]
} -cleanup {
    rename fact {}
} -result {1 120 3628800 1307674368000}


if {[testConstraint tailcall]} {
    namespace forget tcl::unsupported::tailcall
}

# cleanup
::tcltest::cleanupTests

if {[testConstraint testnrelevels]} {
    namespace forget testnre::*
    namespace delete testnre
}

return