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# -*- tcl -*-
# ### ### ### ######### ######### #########
## Package description
## Utility commands for the conversion between various representations
## of abstract syntax trees.
# ### ### ### ######### ######### #########
## Requisites
namespace eval ::grammar::me::util {
namespace export ast2tree ast2etree tree2ast
}
# ### ### ### ######### ######### #########
## Implementation
# ### ### ### ######### ######### #########
## API Implementation.
proc ::grammar::me::util::ast2tree {ast tree {root {}}} {
# See grammar::me_ast for the specification of both value and tree
# representations.
if {$root eq ""} {
set root [$tree rootname]
}
# Decompose the AST value into its components.
if {[llength $ast] < 3} {
return -code error "Bad node \"$ast\", not enough elements"
}
set type [lindex $ast 0]
set range [lrange $ast 1 2]
set children [lrange $ast 3 end]
if {($type eq "") && [llength $children]} {
return -code error \
"Terminal node \"[lrange $ast 0 2]\" has children"
}
foreach {s e} $range break
if {
![string is integer -strict $s] || ($s < 0) ||
![string is integer -strict $e] || ($e < 0)
} {
return -code error "Bad range information \"$range\""
}
# Create a node for the root of the AST and fill it with the data
# from the value. Afterward recurse and build the tree for the
# children of the root.
set new [lindex [$tree insert $root end] 0]
if {$type eq ""} {
$tree set $new type terminal
} else {
$tree set $new type nonterminal
$tree set $new detail $type
}
$tree set $new range $range
foreach child $children {
ast2tree $child $tree $new
}
return
}
proc ::grammar::me::util::ast2etree {ast mcmd tree {root {}}} {
# See grammar::me_ast for the specification of both value and tree
# representations.
if {$root eq ""} {
set root [$tree rootname]
}
# Decompose the AST value into its components.
if {[llength $ast] < 3} {
return -code error "Bad node \"$ast\", not enough elements"
}
set type [lindex $ast 0]
set range [lrange $ast 1 2]
set children [lrange $ast 3 end]
if {($type eq "") && [llength $children]} {
return -code error \
"Terminal node \"[lrange $ast 0 2]\" has children"
}
foreach {s e} $range break
if {
![string is integer -strict $s] || ($s < 0) ||
![string is integer -strict $e] || ($e < 0)
} {
return -code error "Bad range information \"$range\""
}
# Create a node for the root of the AST and fill it with the data
# from the value. Afterward recurse and build the tree for the
# children of the root.
set new [lindex [$tree insert $root end] 0]
if {$type eq ""} {
set cmd $mcmd
lappend cmd tok
foreach loc $range {lappend cmd $loc}
$tree set $new type terminal
$tree set $new detail [uplevel \#0 $cmd]
} else {
$tree set $new type nonterminal
$tree set $new detail $type
}
set range_lc {}
foreach loc $range {
lappend range_lc [uplevel \#0 \
[linsert $mcmd end lc $loc]]
}
$tree set $new range $range
$tree set $new range_lc $range_lc
foreach child $children {
ast2etree $child $mcmd $tree $new
}
return
}
proc ::grammar::me::util::tree2ast {tree {root {}}} {
# See grammar::me_ast for the specification of both value and tree
# representations.
if {$root eq ""} {
set root [$tree rootname]
}
set value {}
if {![$tree keyexists $root type]} {
return -code error "Bad node \"$root\", type information is missing"
}
if {![$tree keyexists $root range]} {
return -code error "Bad node \"$root\", range information is missing"
}
set range [$tree get $root range]
if {[llength $range] != 2} {
return -code error "Bad node \"root\", bad range information \"$range\""
}
foreach {s e} $range break
if {
![string is integer -strict $s] || ($s < 0) ||
![string is integer -strict $e] || ($e < 0)
} {
return -code error "Bad node \"root\", bad range information \"$range\""
}
if {[$tree get $root type] eq "terminal"} {
lappend value {}
} else {
if {![$tree keyexists $root detail]} {
return -code error "Bad node \"$root\", nonterminal detail is missing"
}
lappend value [$tree get $root detail]
}
# Range data ...
lappend value $s $e
foreach child [$tree children $root] {
lappend value [tree2ast $tree $child]
}
return $value
}
# ### ### ### ######### ######### #########
## Package Management
package provide grammar::me::util 0.1
|
