path: root/tests/NRE.test

# Commands covered:  proc, apply, [interp alias], [namespce import], tailcall
#
# This file contains a collection of tests for the non-recursive executor that
# avoids recursive calls to TEBC.
#
# 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: NRE.test,v 1.2 2008/07/16 00:44:44 msofer Exp $

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

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

if {[testConstraint teststacklimit]} {
    #
    # Workaround for gnu-make bug http://savannah.gnu.org/bugs/?18396
    #
    # Do not let make set up too large a C stack for us, as it effectively
    # disables the tests under some circumstances
    #

    set oldLimit [teststacklimit 2048]
}


#
# The first few tests will blow the C stack if the NR machinery is not working
# properly: all these calls should execute within the same instance of TEBC,
# and thus do not load the C stack. The nesting limit is given by how much the
# Tcl execution stack can grow. 
#

interp recursionlimit {} 100000

test NRE-1.1 {self-recursive procs} -setup {
    proc a i {
	if {[incr i] > 20000} {
	    return $i
	}
	a $i
    }
} -body {
    list [catch {a 0} msg] $msg
} -cleanup {
    rename a {}
} -result {0 20001}

test NRE-1.2 {self-recursive lambdas} -setup {
    set a [list i {
	if {[incr i] > 20000} {
	    return $i
	}
	apply $::a $i
    }]
} -body {
    list [catch {apply $a 0} msg] $msg
} -cleanup {
    unset a
} -result {0 20001}

test NRE-1.2.1 {self-recursive lambdas} -setup {
    set a [list {} {
	if {[incr ::i] > 20000} {
	    return $::i
	}
	apply $::a
    }]
} -body {
    set ::i 0
    list [catch {apply $a} msg] $msg $::i
} -cleanup {
    unset a
} -result {0 20001 20001}

test NRE-1.3 {mutually recursive procs and lambdas} -setup {
    proc a i {
	apply $::b [incr i]
    }
    set b [list i {
	if {[incr i] > 20000} {
	    return $i
	}
	a $i
    }]
} -body {
    list [catch {list [a 0] [apply $b 0]} msg] $msg
} -cleanup {
    rename a {}
    unset b
} -result {0 {20002 20001}}

#
# Test that aliases are non-recursive
#

test NRE-2.1 {alias is not recursive} -setup {
    proc a i {
	if {[incr i] > 20000} {
	    return $i
	}
	b $i
    }
    interp alias {} b {} a
} -body {
    list [catch {list [a 0] [b 0]} msg] $msg
} -cleanup {
    rename a {}
    rename b {}
} -result {0 {20001 20001}}

#
# Test that imports are non-recursive
#

test NRE-3.1 {imports are not recursive} -setup {
    namespace eval foo {
	proc a i {
	    if {[incr i] > 20000} {
		return $i
	    }
	    ::a $i
	}
	namespace export a
    }
    namespace import foo::a
    a 1
} -body {
    list [catch {a 0} msg] $msg
} -cleanup {
    rename a {}
    namespace delete ::foo
} -result {0 20001}


test NRE-4.1 {ensembles are not recursive} -setup {
    proc a i {
	if {[incr i] > 20000} {
	    return $i
	}
	b foo $i
    }
    namespace ensemble create \
	-command b \
	-map [list foo a]
} -body {
    list [catch {list [a 0] [b foo 0]} msg] $msg
} -cleanup {
    rename a {}
    rename b {}
} -result {0 {20001 20001}}


test NRE-5.1 {[namespace eval] is not recursive} -setup {
    namespace eval ::foo {
	proc a i {
	    if {[incr i] > 20000} {
		return $i
	    }
	    namespace eval ::foo [list a $i]
	}
    }
} -body {
    list [catch {::foo::a 0} msg] $msg
} -cleanup {
    namespace delete ::foo
} -result {0 20001}

test NRE-5.2 {[namespace eval] is not recursive} -setup {
    namespace eval ::foo {
	proc a i {
	    if {[incr i] > 20000} {
		return $i
	    }
	    namespace eval ::foo "set x $i; a $i"
	}
    }
} -body {
    list [catch {::foo::a 0} msg] $msg
} -cleanup {
    namespace delete ::foo
} -result {0 20001}


test NRE-6.1 {[uplevel] is not recursive} -setup {
    proc a i {
	if {[incr i] > 20000} {
	    return $i
	}
	uplevel 1 [list a $i]
    }
} -body {
    list [catch {a 0} msg] $msg
} -cleanup {
    rename a {}
} -result {0 20001}

test NRE-6.2 {[uplevel] is not recursive} -setup {
    proc a i {
	if {[incr i] > 20000} {
	    return $i
	}
	uplevel 1 "set x $i; a $i"
    }
} -body {
    list [catch {a 0} msg] $msg
} -cleanup {
    rename a {}
} -result {0 20001}

#
# NASTY BUG found by tcllib's interp package
#

test NRE-X.1 {eval in wrong interp} {
    set i [interp create]
    set res [$i eval {
	set x {namespace children ::}
	set y [list namespace children ::]
	namespace delete {*}[{*}$y]
	set j [interp create]
	$j eval {namespace delete {*}[namespace children ::]}
	namespace eval foo {}
	set res [list [eval $x] [eval $y] [$j eval $x] [$j eval $y]]
	interp delete $j
	set res
    }]
    interp delete $i
    set res
} {::foo ::foo {} {}}

#
# Test tailcalls
#
namespace eval tcl::unsupported namespace export tailcall
namespace import tcl::unsupported::tailcall

test NRE-T.1 {tailcall} {tailcall} {
    namespace eval a {
	unset -nocomplain x
	proc aset args {uplevel 1 [list set {*}$args]}
	proc foo {} {tailcall aset x 1}
    }
    namespace eval b {
	unset -nocomplain x
	proc aset args {error b::aset}
	proc moo {} {set x 0; ::a::foo; set x}
    }
    unset -nocomplain x
    proc aset args {error ::aset}
    ::b::moo
} 1

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

test NRE-T.3 {tailcall falls off tebc} {tailcall} {
    unset -nocomplain x
    proc foo {} {tailcall set x 1}
    list [catch foo msg] $msg [set x]
} {0 1 1}

test NRE-T.4 {tailcall falls off tebc} {
    set x 2
    proc foo {} {tailcall set x 1}
    foo
    set x
} 1

test NRE-T.5 {tailcall falls off tebc} {
    set x 2
    namespace eval bar {
	variable x 3
	proc foo {} {tailcall set x 1}
    }
    foo
    list $x $bar::x
} {1 3}

test NRE-T.6 {tailcall does remove callframes} {tailcall} {
    proc foo {} {info level}
    proc moo {} {tailcall foo}
    proc boo {} {expr {[moo] - [info level]}}
    boo
} 1


#
# Test that ensembles are non-recursive
#



# cleanup
::tcltest::cleanupTests

if {[testConstraint teststacklimit]} {
    teststacklimit $oldLimit
}


return