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Overview
| Comment: | The drop operation should only be permissive on choices (reflecting the realizability condition on choice). New expressions should not be constructed for expressions other than choice. |
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| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | pt-container-ssoberni |
| Files: | files | file ages | folders |
| SHA3-256: |
f70ef61b952a738698e5c08e0016dbe4 |
| User & Date: | ssoberni 2018-06-14 14:31:51.627 |
Context
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2018-06-27
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| 17:16 | Update peg container transform work to latest trunk, including peg ffp fixes. check-in: 63282d761b user: aku tags: pt-container-ssoberni | |
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2018-06-14
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| 14:31 | The drop operation should only be permissive on choices (reflecting the realizability condition on choice). New expressions should not be constructed for expressions other than choice. check-in: f70ef61b95 user: ssoberni tags: pt-container-ssoberni | |
| 14:02 | Kleene star and optionals are better deemed realizable by definition. check-in: 8cd8a7435f user: ssoberni tags: pt-container-ssoberni | |
Changes
Changes to modules/pt/pt_pexpr_op.tcl.
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# # ## ### ##### ######## #############
## Internals
proc ::pt::pe::op::Drop {dropset pe op arguments} {
if {$op eq "n"} {
lassign $arguments symbol
if {[struct::set contains $dropset $symbol]} {
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# # ## ### ##### ######## #############
## Internals
proc ::pt::pe::op::Drop {dropset pe op arguments} {
if {$op eq "n"} {
lassign $arguments symbol
if {[struct::set contains $dropset $symbol]} {
set pe @@
}
} elseif {$op in {/ x * + ? & !}} {
set newarg {}
foreach a $arguments {
if {$a eq "@@"} continue
lappend newarg $a
}
if {![llength $newarg]} {
# Nothing remained, drop the whole expression
set pe [pt::pe epsilon]
} elseif {[llength $newarg] < [llength $arguments]} {
# Some removed, construct a new expression
if {$op eq "/"} {
set pe [list $op {*}$newarg]
} else {
set pe @@
}
} ; # None removed, no change.
}
return $pe
}
proc ::pt::pe::op::Rename {nt ntnew pe op arguments} {
#puts R($op)/$arguments/
if {($op eq "n") && ([lindex $arguments 0] eq $nt)} {
return [pt::pe nonterminal $ntnew]
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