diff --git a/basis/checksums/sha1/sha1.factor b/basis/checksums/sha1/sha1.factor
index e75ebfb9e4..0ddb429b28 100755
--- a/basis/checksums/sha1/sha1.factor
+++ b/basis/checksums/sha1/sha1.factor
@@ -127,7 +127,7 @@ M: sha1 checksum-stream ( stream -- sha1 )
     [ zip concat ] keep like ;
 
 : sha1-interleave ( string -- seq )
-    [ zero? ] left-trim
+    [ zero? ] trim-left
     dup length odd? [ rest ] when
     seq>2seq [ sha1 checksum-bytes ] bi@
     2seq>seq ;
diff --git a/basis/compiler/tree/normalization/normalization.factor b/basis/compiler/tree/normalization/normalization.factor
index 12c7a60ec8..08481726dc 100644
--- a/basis/compiler/tree/normalization/normalization.factor
+++ b/basis/compiler/tree/normalization/normalization.factor
@@ -151,7 +151,7 @@ M: #branch normalize*
 : eliminate-phi-introductions ( introductions seq terminated -- seq' )
     [
         [ nip ] [
-            dup [ +bottom+ eq? ] left-trim
+            dup [ +bottom+ eq? ] trim-left
             [ [ length ] bi@ - tail* ] keep append
         ] if
     ] 3map ;
diff --git a/basis/help/help-docs.factor b/basis/help/help-docs.factor
index 47cc2987d7..643e121f5e 100755
--- a/basis/help/help-docs.factor
+++ b/basis/help/help-docs.factor
@@ -14,6 +14,7 @@ ARTICLE: "span-elements" "Span elements"
 { $subsection $link }
 { $subsection $vocab-link }
 { $subsection $snippet }
+{ $subsection $slot }
 { $subsection $url } ;
 
 ARTICLE: "block-elements" "Block elements"
@@ -212,6 +213,18 @@ HELP: $code
     { $markup-example { $code "2 2 + ." } }
 } ;
 
+HELP: $nl
+{ $values { "children" "unused parameter" } }
+{ $description "Prints a paragraph break. The parameter is unused." } ;
+
+HELP: $snippet
+{ $values { "children" "markup elements" } }
+{ $description "Prints a key word or otherwise notable snippet of text, such as a type or a word input parameter. To document slot names, use " { $link $slot } "." } ;
+
+HELP: $slot
+{ $values { "children" "markup elements" } }
+{ $description "Prints a tuple slot name in the same way as a snippet. The help tool can check that there exists an accessor with this name." } ;
+
 HELP: $vocabulary
 { $values { "element" "a markup element of the form " { $snippet "{ word }" } } }
 { $description "Prints a word's vocabulary. This markup element is automatically output by the help system, so help descriptions of parsing words should not call it." } ;
diff --git a/basis/help/markup/markup.factor b/basis/help/markup/markup.factor
index d65eb8fc88..d94b9c4b41 100755
--- a/basis/help/markup/markup.factor
+++ b/basis/help/markup/markup.factor
@@ -3,7 +3,7 @@
 USING: accessors arrays definitions generic io kernel assocs
 hashtables namespaces parser prettyprint sequences strings
 io.styles vectors words math sorting splitting classes slots
-vocabs help.stylesheet help.topics vocabs.loader ;
+vocabs help.stylesheet help.topics vocabs.loader alias ;
 IN: help.markup
 
 ! Simple markup language.
@@ -61,6 +61,9 @@ M: f print-element drop ;
 : $snippet ( children -- )
     [ snippet-style get print-element* ] ($span) ;
 
+! for help-lint
+ALIAS: $slot $snippet
+
 : $emphasis ( children -- )
     [ emphasis-style get print-element* ] ($span) ;
 
diff --git a/basis/http/client/client.factor b/basis/http/client/client.factor
index ea1cfd9a4b..8dc1924a12 100755
--- a/basis/http/client/client.factor
+++ b/basis/http/client/client.factor
@@ -113,7 +113,7 @@ SYMBOL: redirects
 PRIVATE>
 
 : read-chunk-size ( -- n )
-    read-crlf ";" split1 drop [ blank? ] right-trim
+    read-crlf ";" split1 drop [ blank? ] trim-right
     hex> [ "Bad chunk size" throw ] unless* ;
 
 : read-chunks ( -- )
diff --git a/basis/http/server/static/static.factor b/basis/http/server/static/static.factor
index 98510e45fd..dfbe93d86d 100755
--- a/basis/http/server/static/static.factor
+++ b/basis/http/server/static/static.factor
@@ -45,9 +45,9 @@ TUPLE: file-responder root hook special allow-listings ;
     [ file-responder get hook>> call ] [ 2drop <304> ] if ;
 
 : serving-path ( filename -- filename )
-    file-responder get root>> right-trim-separators
+    file-responder get root>> trim-right-separators
     "/"
-    rot "" or left-trim-separators 3append ;
+    rot "" or trim-left-separators 3append ;
 
 : serve-file ( filename -- response )
     dup mime-type
diff --git a/basis/io/monitors/monitors-tests.factor b/basis/io/monitors/monitors-tests.factor
index 63381811d1..1cc97753b7 100755
--- a/basis/io/monitors/monitors-tests.factor
+++ b/basis/io/monitors/monitors-tests.factor
@@ -54,7 +54,7 @@ os { winnt linux macosx } member? [
                     "m" get next-change drop
                     dup print flush
                     dup parent-directory
-                    [ right-trim-separators "xyz" tail? ] either? not
+                    [ trim-right-separators "xyz" tail? ] either? not
                 ] loop
 
                 "c1" get count-down
@@ -63,7 +63,7 @@ os { winnt linux macosx } member? [
                     "m" get next-change drop
                     dup print flush
                     dup parent-directory
-                    [ right-trim-separators "yxy" tail? ] either? not
+                    [ trim-right-separators "yxy" tail? ] either? not
                 ] loop
 
                 "c2" get count-down
diff --git a/basis/io/windows/nt/files/files-tests.factor b/basis/io/windows/nt/files/files-tests.factor
index 0fa4b4151c..830861eba0 100755
--- a/basis/io/windows/nt/files/files-tests.factor
+++ b/basis/io/windows/nt/files/files-tests.factor
@@ -21,8 +21,8 @@ IN: io.windows.nt.files.tests
 [ t ] [ "\\\\" root-directory? ] unit-test
 [ t ] [ "/" root-directory? ] unit-test
 [ t ] [ "//" root-directory? ] unit-test
-[ t ] [ "c:\\" right-trim-separators root-directory? ] unit-test
-[ t ] [ "Z:\\" right-trim-separators root-directory? ] unit-test
+[ t ] [ "c:\\" trim-right-separators root-directory? ] unit-test
+[ t ] [ "Z:\\" trim-right-separators root-directory? ] unit-test
 [ f ] [ "c:\\foo" root-directory? ] unit-test
 [ f ] [ "." root-directory? ] unit-test
 [ f ] [ ".." root-directory? ] unit-test
diff --git a/basis/io/windows/nt/files/files.factor b/basis/io/windows/nt/files/files.factor
index 6a890f6392..5fbacfa325 100755
--- a/basis/io/windows/nt/files/files.factor
+++ b/basis/io/windows/nt/files/files.factor
@@ -22,7 +22,7 @@ M: winnt root-directory? ( path -- ? )
     {
         { [ dup empty? ] [ f ] }
         { [ dup [ path-separator? ] all? ] [ t ] }
-        { [ dup right-trim-separators { [ length 2 = ] [ second CHAR: : = ] } 1&& ] [ t ] }
+        { [ dup trim-right-separators { [ length 2 = ] [ second CHAR: : = ] } 1&& ] [ t ] }
         [ f ]
     } cond nip ;
 
diff --git a/extra/match/authors.txt b/basis/match/authors.txt
similarity index 100%
rename from extra/match/authors.txt
rename to basis/match/authors.txt
diff --git a/extra/match/match-docs.factor b/basis/match/match-docs.factor
similarity index 100%
rename from extra/match/match-docs.factor
rename to basis/match/match-docs.factor
diff --git a/extra/match/match-tests.factor b/basis/match/match-tests.factor
similarity index 100%
rename from extra/match/match-tests.factor
rename to basis/match/match-tests.factor
diff --git a/extra/match/match.factor b/basis/match/match.factor
similarity index 100%
rename from extra/match/match.factor
rename to basis/match/match.factor
diff --git a/extra/match/summary.txt b/basis/match/summary.txt
similarity index 100%
rename from extra/match/summary.txt
rename to basis/match/summary.txt
diff --git a/extra/match/tags.txt b/basis/match/tags.txt
similarity index 100%
rename from extra/match/tags.txt
rename to basis/match/tags.txt
diff --git a/basis/peg/peg.factor b/basis/peg/peg.factor
index 0cf0382ee2..dbb3a04a09 100755
--- a/basis/peg/peg.factor
+++ b/basis/peg/peg.factor
@@ -513,18 +513,11 @@ TUPLE: action-parser p1 quot ;
 M: action-parser (compile) ( peg -- quot )
   [ p1>> compile-parser 1quotation ] [ quot>> ] bi '[ @ , check-action ] ;
 
-: left-trim-slice ( string -- string )
-  #! Return a new string without any leading whitespace
-  #! from the original string.
-  dup empty? [
-    dup first blank? [ rest-slice left-trim-slice ] when
-  ] unless ;
-
 TUPLE: sp-parser p1 ;
 
 M: sp-parser (compile) ( peg -- quot )
   p1>> compile-parser 1quotation '[ 
-    input-slice left-trim-slice input-from pos set @ 
+    input-slice trim-left-slice input-from pos set @ 
   ] ;
 
 TUPLE: delay-parser quot ;
diff --git a/basis/tools/annotations/annotations-docs.factor b/basis/tools/annotations/annotations-docs.factor
index affb95c761..f0a3235e62 100755
--- a/basis/tools/annotations/annotations-docs.factor
+++ b/basis/tools/annotations/annotations-docs.factor
@@ -1,4 +1,5 @@
-USING: help.markup help.syntax words parser ;
+USING: help.markup help.syntax words parser quotations strings
+system sequences ;
 IN: tools.annotations
 
 ARTICLE: "tools.annotations" "Word annotations"
@@ -20,6 +21,8 @@ HELP: watch
 { $values { "word" word } }
 { $description "Annotates a word definition to print the data stack on entry and exit." } ;
 
+{ watch watch-vars reset } related-words
+
 HELP: breakpoint
 { $values { "word" word } }
 { $description "Annotates a word definition to enter the single stepper when executed." } ;
@@ -27,3 +30,36 @@ HELP: breakpoint
 HELP: breakpoint-if
 { $values { "quot" "a quotation with stack effect" { $snippet "( -- ? )" } } { "word" word } }
 { $description "Annotates a word definition to enter the single stepper if the quotation yields true." } ;
+
+HELP: annotate-methods
+{ $values
+     { "word" word } { "quot" quotation } }
+{ $description "Annotates the word -- for generic words, all its methods -- with the quotation." } ;
+
+HELP: entering
+{ $values
+     { "str" string } }
+{ $description "Prints a message and the inputs to the word before the word has been called." } ;
+
+HELP: leaving
+{ $values
+     { "str" string } }
+{ $description "Prints a message and the outputs from a word after a word has been called." } ;
+
+HELP: reset
+{ $values
+     { "word" word } }
+{ $description "Resets any annotations on a word." }
+{ $notes "This word will remove a " { $link watch } "." } ;
+
+HELP: watch-vars
+{ $values
+     { "word" word } { "vars" "a sequence of symbols" } }
+{ $description "Annotates a word definition to print the " { $snippet "vars" } " upon entering the word. This word is useful for debugging." } ;
+
+HELP: word-inputs
+{ $values
+     { "word" word }
+     { "seq" sequence } }
+{ $description "Makes a sequence of the inputs to a word by counting the number of inputs in the stack effect and saving that many items from the datastack." } ;
+
diff --git a/basis/tools/scaffold/scaffold.factor b/basis/tools/scaffold/scaffold.factor
index 1312681f85..74c92605aa 100644
--- a/basis/tools/scaffold/scaffold.factor
+++ b/basis/tools/scaffold/scaffold.factor
@@ -4,7 +4,7 @@ USING: assocs io.files hashtables kernel namespaces sequences
 vocabs.loader io combinators io.encodings.utf8 calendar accessors
 math.parser io.streams.string ui.tools.operations quotations
 strings arrays prettyprint words vocabs sorting sets
-classes ;
+classes alien ;
 IN: tools.scaffold
 
 SYMBOL: developer-name
@@ -95,6 +95,7 @@ ERROR: no-vocab vocab ;
         { "obj3" object } { "obj4" object }
         { "quot" quotation } { "quot1" quotation }
         { "quot2" quotation } { "quot3" quotation }
+        { "quot'" quotation }
         { "string" string } { "string1" string }
         { "string2" string } { "string3" string }
         { "str" string }
@@ -105,9 +106,20 @@ ERROR: no-vocab vocab ;
         { "ch" "a character" }
         { "word" word }
         { "array" array }
+        { "duration" duration }
         { "path" "a pathname string" }
         { "vocab" "a vocabulary specifier" }
         { "vocab-root" "a vocabulary root string" }
+        { "c-ptr" c-ptr }
+        { "seq" sequence } { "seq1" sequence } { "seq2" sequence }
+        { "seq3" sequence } { "seq4" sequence }
+        { "seq1'" sequence } { "seq2'" sequence }
+        { "newseq" sequence } 
+        { "assoc" assoc } { "assoc1" assoc } { "assoc2" assoc }
+        { "assoc3" assoc } { "newassoc" assoc }
+        { "alist" "an array of key/value pairs" }
+        { "keys" sequence } { "values" sequence }
+        { "class" class }
     } at* ;
 
 : add-using ( object -- )
@@ -227,3 +239,20 @@ PRIVATE>
         [ drop scaffold-authors ]
         [ nip require ]
     } 2cleave ;
+
+SYMBOL: examples-flag
+
+: example ( -- )
+    {
+        "{ $example \"\" \"USING: prettyprint ;\""
+        "           \"\""
+        "           \"\""
+        "}"
+    } [ examples-flag get [ "    " write ] when print ] each ;
+
+: examples ( n -- )
+    t \ examples-flag [
+        "{ $examples " print
+        [ example ] times
+        "}" print
+    ] with-variable ;
diff --git a/basis/tools/vocabs/monitor/monitor.factor b/basis/tools/vocabs/monitor/monitor.factor
index 12b2e41d36..ed2e486ecc 100755
--- a/basis/tools/vocabs/monitor/monitor.factor
+++ b/basis/tools/vocabs/monitor/monitor.factor
@@ -9,8 +9,8 @@ IN: tools.vocabs.monitor
 TR: convert-separators "/\\" ".." ;
 
 : vocab-dir>vocab-name ( path -- vocab )
-    left-trim-separators
-    right-trim-separators
+    trim-left-separators
+    trim-right-separators
     convert-separators ;
 
 : path>vocab-name ( path -- vocab )
diff --git a/basis/unicode/collation/collation.factor b/basis/unicode/collation/collation.factor
index b5c7665b8b..d71fffaaab 100755
--- a/basis/unicode/collation/collation.factor
+++ b/basis/unicode/collation/collation.factor
@@ -136,7 +136,7 @@ PRIVATE>
 : insensitive= ( str1 str2 levels-removed -- ? )
     [
         swap collation-key swap
-        [ [ 0 = not ] right-trim but-last ] times
+        [ [ 0 = not ] trim-right but-last ] times
     ] curry bi@ = ;
 PRIVATE>
 
diff --git a/core/combinators/combinators-docs.factor b/core/combinators/combinators-docs.factor
index 67fde74a92..a494c09b05 100755
--- a/core/combinators/combinators-docs.factor
+++ b/core/combinators/combinators-docs.factor
@@ -16,6 +16,10 @@ $nl
 { $subsection while }
 "Generalization of " { $link bi } " and " { $link tri } ":"
 { $subsection cleave }
+"Generalization of " { $link 2bi } " and " { $link 2tri } ":"
+{ $subsection 2cleave }
+"Generalization of " { $link 3bi } " and " { $link 3tri }  ":"
+{ $subsection 3cleave }
 "Generalization of " { $link bi* } " and " { $link tri* } ":"
 { $subsection spread }
 "Two combinators which abstract out nested chains of " { $link if } ":"
@@ -50,6 +54,16 @@ HELP: cleave
     }
 } ;
 
+HELP: 2cleave
+{ $values { "x" object } { "y" object }
+          { "seq" "a sequence of quotations with stack effect " { $snippet "( x y -- ... )" } } }
+{ $description "Applies each quotation to the two objects in turn." } ;
+
+HELP: 3cleave
+{ $values { "x" object } { "y" object } { "z" object }
+          { "seq" "a sequence of quotations with stack effect " { $snippet "( x y z -- ... )" } } }
+{ $description "Applies each quotation to the three objects in turn." } ;
+
 { bi tri cleave } related-words
 
 HELP: spread
diff --git a/core/combinators/combinators.factor b/core/combinators/combinators.factor
index d0c83d0ca2..4a362a7f9d 100755
--- a/core/combinators/combinators.factor
+++ b/core/combinators/combinators.factor
@@ -13,14 +13,14 @@ IN: combinators
     [ [ keep ] curry ] map concat [ drop ] append [ ] like ;
 
 ! 2cleave
-: 2cleave ( x seq -- )
+: 2cleave ( x y seq -- )
     [ 2keep ] each 2drop ;
 
 : 2cleave>quot ( seq -- quot )
     [ [ 2keep ] curry ] map concat [ 2drop ] append [ ] like ;
 
 ! 3cleave
-: 3cleave ( x seq -- )
+: 3cleave ( x y z seq -- )
     [ 3keep ] each 3drop ;
 
 : 3cleave>quot ( seq -- quot )
diff --git a/core/io/files/files.factor b/core/io/files/files.factor
index cf87506bf9..93405fe7c0 100755
--- a/core/io/files/files.factor
+++ b/core/io/files/files.factor
@@ -47,11 +47,11 @@ HOOK: (file-appender) io-backend ( path -- stream )
 
 : path-separator ( -- string ) os windows? "\\" "/" ? ;
 
-: right-trim-separators ( str -- newstr )
-    [ path-separator? ] right-trim ;
+: trim-right-separators ( str -- newstr )
+    [ path-separator? ] trim-right ;
 
-: left-trim-separators ( str -- newstr )
-    [ path-separator? ] left-trim ;
+: trim-left-separators ( str -- newstr )
+    [ path-separator? ] trim-left ;
 
 : last-path-separator ( path -- n ? )
     [ length 1- ] keep [ path-separator? ] find-last-from ;
@@ -65,7 +65,7 @@ ERROR: no-parent-directory path ;
 
 : parent-directory ( path -- parent )
     dup root-directory? [
-        right-trim-separators
+        trim-right-separators
         dup last-path-separator [
             1+ cut
         ] [
@@ -92,7 +92,7 @@ ERROR: no-parent-directory path ;
 : append-path-empty ( path1 path2 -- path' )
     {
         { [ dup head.? ] [
-            rest left-trim-separators append-path-empty
+            rest trim-left-separators append-path-empty
         ] }
         { [ dup head..? ] [ drop no-parent-directory ] }
         [ nip ]
@@ -121,19 +121,19 @@ PRIVATE>
     {
         { [ over empty? ] [ append-path-empty ] }
         { [ dup empty? ] [ drop ] }
-        { [ over right-trim-separators "." = ] [ nip ] }
+        { [ over trim-right-separators "." = ] [ nip ] }
         { [ dup absolute-path? ] [ nip ] }
-        { [ dup head.? ] [ rest left-trim-separators append-path ] }
+        { [ dup head.? ] [ rest trim-left-separators append-path ] }
         { [ dup head..? ] [
-            2 tail left-trim-separators
+            2 tail trim-left-separators
             >r parent-directory r> append-path
         ] }
         { [ over absolute-path? over first path-separator? and ] [
             >r 2 head r> append
         ] }
         [
-            >r right-trim-separators "/" r>
-            left-trim-separators 3append
+            >r trim-right-separators "/" r>
+            trim-left-separators 3append
         ]
     } cond ;
 
@@ -142,7 +142,7 @@ PRIVATE>
 
 : file-name ( path -- string )
     dup root-directory? [
-        right-trim-separators
+        trim-right-separators
         dup last-path-separator [ 1+ tail ] [
             drop "resource:" ?head [ file-name ] when
         ] if
@@ -200,7 +200,7 @@ SYMBOL: current-directory
 
 : (normalize-path) ( path -- path' )
     "resource:" ?head [
-        left-trim-separators resource-path
+        trim-left-separators resource-path
         (normalize-path)
     ] [
         current-directory get prepend-path
@@ -219,7 +219,7 @@ M: object normalize-path ( path -- path' )
 HOOK: make-directory io-backend ( path -- )
 
 : make-directories ( path -- )
-    normalize-path right-trim-separators {
+    normalize-path trim-right-separators {
         { [ dup "." = ] [ ] }
         { [ dup root-directory? ] [ ] }
         { [ dup empty? ] [ ] }
diff --git a/core/sequences/sequences-docs.factor b/core/sequences/sequences-docs.factor
index baf68db112..4ada1ece9a 100755
--- a/core/sequences/sequences-docs.factor
+++ b/core/sequences/sequences-docs.factor
@@ -178,6 +178,16 @@ ARTICLE: "sequences-search" "Searching sequences"
 { $subsection find-last }
 { $subsection find-last-from } ;
 
+ARTICLE: "sequences-trimming" "Trimming sequences"
+"Trimming words:"
+{ $subsection trim }
+{ $subsection trim-left }
+{ $subsection trim-right }
+"Potentially more efficient trim:"
+{ $subsection trim-slice }
+{ $subsection trim-left-slice }
+{ $subsection trim-right-slice } ;
+
 ARTICLE: "sequences-destructive" "Destructive operations"
 "These words modify their input, instead of creating a new sequence."
 $nl
@@ -245,6 +255,7 @@ $nl
 { $subsection "sequences-sorting" }
 { $subsection "binary-search" }
 { $subsection "sets" }
+{ $subsection "sequences-trimming" }
 "For inner loops:"
 { $subsection "sequences-unsafe" } ;
 
@@ -731,7 +742,7 @@ HELP: reverse-here
 
 HELP: padding
 { $values { "seq" sequence } { "n" "a non-negative integer" } { "elt" object } { "quot" "a quotation with stack effect " { $snippet "( seq1 seq2 -- newseq )" } } { "newseq" "a new sequence" } }
-{ $description "Outputs a new string sequence of " { $snippet "elt" } " repeated, that when appended to " { $snippet "seq" } ", yields a sequence of length " { $snippet "n" } ". If the length of { " { $snippet "seq" } " is greater than " { $snippet "n" } ", this word outputs an empty sequence." } ;
+{ $description "Outputs a new string sequence of " { $snippet "elt" } " repeated, that when appended to " { $snippet "seq" } ", yields a sequence of length " { $snippet "n" } ". If the length of " { $snippet "seq" } " is greater than " { $snippet "n" } ", this word outputs an empty sequence." } ;
 
 HELP: pad-left
 { $values { "seq" sequence } { "n" "a non-negative integer" } { "elt" object } { "padded" "a new sequence" } }
@@ -1004,3 +1015,45 @@ HELP: count
     "50"
 } ;
 
+HELP: pusher
+{ $values
+     { "quot" "a predicate quotation" }
+     { "quot" quotation } { "accum" vector } }
+{ $description "Creates a new vector to accumulate the values which return true for a predicate.  Returns a new quotation which accepts an object to be tested and stored in the accumulator if the test yields true. The accumulator is left on the stack for convenience." }
+{ $example "! Find all the even numbers:" "USING: prettyprint sequences math kernel ;"
+           "10 [ even? ] pusher [ each ] dip ."
+           "V{ 0 2 4 6 8 }"
+}
+{ $notes "Used to implement the " { $link filter } " word." } ;
+
+HELP: trim-left
+{ $values
+     { "seq" sequence } { "quot" quotation }
+     { "newseq" sequence } }
+{ $description "Removes elements starting from the left side of a sequence if they match a predicate. Once an element does not match, the test stops and the rest of the sequence is left on the stack as a new sequence." }
+{ $example "" "USING: prettyprint math sequences ;"
+           "{ 0 0 1 2 3 0 0 } [ zero? ] trim-left ."
+           "{ 1 2 3 0 0 }"
+} ;
+
+HELP: trim-right
+{ $values
+     { "seq" sequence } { "quot" quotation }
+     { "newseq" sequence } }
+{ $description "Removes elements starting from the right side of a sequence if they match a predicate. Once an element does not match, the test stops and the rest of the sequence is left on the stack as a new sequence." }
+{ $example "" "USING: prettyprint math sequences ;"
+           "{ 0 0 1 2 3 0 0 } [ zero? ] trim-right ."
+           "{ 0 0 1 2 3 }"
+} ;
+
+HELP: trim
+{ $values
+     { "seq" sequence } { "quot" quotation }
+     { "newseq" sequence } }
+{ $description "Removes elements starting from the left and right sides of a sequence if they match a predicate. Once an element does not match, the test stops and the rest of the sequence is left on the stack as a new sequence." }
+{ $example "" "USING: prettyprint math sequences ;"
+           "{ 0 0 1 2 3 0 0 } [ zero? ] trim ."
+           "{ 1 2 3 }"
+} ;
+
+{ trim-left trim-right trim } related-words
diff --git a/core/sequences/sequences-tests.factor b/core/sequences/sequences-tests.factor
index 8d7a0469a0..8018fe1cdc 100755
--- a/core/sequences/sequences-tests.factor
+++ b/core/sequences/sequences-tests.factor
@@ -237,13 +237,13 @@ unit-test
 
 [ -1./0. 0 delete-nth ] must-fail
 [ "" ] [ "" [ CHAR: \s = ] trim ] unit-test
-[ "" ] [ "" [ CHAR: \s = ] left-trim ] unit-test
-[ "" ] [ "" [ CHAR: \s = ] right-trim ] unit-test
-[ "" ] [ "  " [ CHAR: \s = ] left-trim ] unit-test
-[ "" ] [ "  " [ CHAR: \s = ] right-trim ] unit-test
+[ "" ] [ "" [ CHAR: \s = ] trim-left ] unit-test
+[ "" ] [ "" [ CHAR: \s = ] trim-right ] unit-test
+[ "" ] [ "  " [ CHAR: \s = ] trim-left ] unit-test
+[ "" ] [ "  " [ CHAR: \s = ] trim-right ] unit-test
 [ "asdf" ] [ " asdf " [ CHAR: \s = ] trim ] unit-test
-[ "asdf " ] [ " asdf " [ CHAR: \s = ] left-trim ] unit-test
-[ " asdf" ] [ " asdf " [ CHAR: \s = ] right-trim ] unit-test
+[ "asdf " ] [ " asdf " [ CHAR: \s = ] trim-left ] unit-test
+[ " asdf" ] [ " asdf " [ CHAR: \s = ] trim-right ] unit-test
 
 [ 328350 ] [ 100 [ sq ] sigma ] unit-test
 
diff --git a/core/sequences/sequences.factor b/core/sequences/sequences.factor
index 2ce939d96f..32671fc7f0 100755
--- a/core/sequences/sequences.factor
+++ b/core/sequences/sequences.factor
@@ -748,16 +748,25 @@ PRIVATE>
     dup slice? [ { } like ] when 0 over length rot <slice> ;
     inline
 
-: left-trim ( seq quot -- newseq )
+: trim-left-slice ( seq quot -- slice )
     over >r [ not ] compose find drop r> swap
-    [ tail ] [ dup length tail ] if* ; inline
+    [ tail-slice ] [ dup length tail-slice ] if* ; inline
+    
+: trim-left ( seq quot -- newseq )
+    over [ trim-left-slice ] dip like ; inline
 
-: right-trim ( seq quot -- newseq )
+: trim-right-slice ( seq quot -- slice )
     over >r [ not ] compose find-last drop r> swap
-    [ 1+ head ] [ 0 head ] if* ; inline
+    [ 1+ head-slice ] [ 0 head-slice ] if* ; inline
+
+: trim-right ( seq quot -- newseq )
+    over [ trim-right-slice ] dip like ; inline
+
+: trim-slice ( seq quot -- slice )
+    [ trim-left-slice ] [ trim-right-slice ] bi ;
 
 : trim ( seq quot -- newseq )
-    [ left-trim ] [ right-trim ] bi ; inline
+    over [ trim-slice ] dip like ; inline
 
 : sum ( seq -- n ) 0 [ + ] binary-reduce ;
 
diff --git a/extra/math/polynomials/polynomials.factor b/extra/math/polynomials/polynomials.factor
index e3adf2277d..1883f56929 100644
--- a/extra/math/polynomials/polynomials.factor
+++ b/extra/math/polynomials/polynomials.factor
@@ -22,7 +22,7 @@ PRIVATE>
 : p= ( p p -- ? ) pextend = ;
 
 : ptrim ( p -- p )
-    dup length 1 = [ [ zero? ] right-trim ] unless ;
+    dup length 1 = [ [ zero? ] trim-right ] unless ;
 
 : 2ptrim ( p p -- p p ) [ ptrim ] bi@ ;
 : p+ ( p p -- p ) pextend v+ ;
diff --git a/extra/pack/pack.factor b/extra/pack/pack.factor
index adceab72f6..b487b385b9 100755
--- a/extra/pack/pack.factor
+++ b/extra/pack/pack.factor
@@ -84,7 +84,7 @@ M: string b, ( n string -- ) heap-size b, ;
     "\0" read-until [ drop f ] unless ;
 
 : read-c-string* ( n -- str/f )
-    read [ zero? ] right-trim dup empty? [ drop f ] when ;
+    read [ zero? ] trim-right dup empty? [ drop f ] when ;
 
 : (read-128-ber) ( n -- n )
     read1
diff --git a/extra/parser-combinators/parser-combinators.factor b/extra/parser-combinators/parser-combinators.factor
index da723bae9d..0ee91bc326 100755
--- a/extra/parser-combinators/parser-combinators.factor
+++ b/extra/parser-combinators/parser-combinators.factor
@@ -175,11 +175,11 @@ M: or-parser parse ( input parser1 -- list )
     parsers>> 0 swap seq>list
     [ parse ] lazy-map-with lconcat ;
 
-: left-trim-slice ( string -- string )
+: trim-left-slice ( string -- string )
     #! Return a new string without any leading whitespace
     #! from the original string.
     dup empty? [
-        dup first blank? [ rest-slice left-trim-slice ] when
+        dup first blank? [ rest-slice trim-left-slice ] when
     ] unless ;
 
 TUPLE: sp-parser p1 ;
@@ -191,7 +191,7 @@ C: sp sp-parser ( p1 -- parser )
 M: sp-parser parse ( input parser -- list )
     #! Skip all leading whitespace from the input then call
     #! the parser on the remaining input.
-    >r left-trim-slice r> p1>> parse ;
+    >r trim-left-slice r> p1>> parse ;
 
 TUPLE: just-parser p1 ;
 
diff --git a/extra/project-euler/059/059.factor b/extra/project-euler/059/059.factor
index 7cc6df3525..aa2cdb75b0 100644
--- a/extra/project-euler/059/059.factor
+++ b/extra/project-euler/059/059.factor
@@ -53,7 +53,7 @@ IN: project-euler.059
 
 : source-059 ( -- seq )
     "resource:extra/project-euler/059/cipher1.txt"
-    ascii file-contents [ blank? ] right-trim "," split
+    ascii file-contents [ blank? ] trim-right "," split
     [ string>number ] map ;
 
 TUPLE: rollover seq n ;
diff --git a/extra/soundex/soundex.factor b/extra/soundex/soundex.factor
index 23d5ee4d4c..d0da0b1347 100644
--- a/extra/soundex/soundex.factor
+++ b/extra/soundex/soundex.factor
@@ -15,7 +15,7 @@ TR: soundex-tr
     [ 2 <clumps> [ = not ] assoc-filter values ] [ first ] bi prefix ;
 
 : first>upper ( seq -- seq' ) 1 head >upper ;
-: trim-first ( seq -- seq' ) dup first [ = ] curry left-trim ;
+: trim-first ( seq -- seq' ) dup first [ = ] curry trim-left ;
 : remove-zeroes ( seq -- seq' ) CHAR: 0 swap remove ;
 : remove-non-alpha ( seq -- seq' ) [ alpha? ] filter ;
 : pad-4 ( first seq -- seq' ) "000" 3append 4 head ;
diff --git a/extra/tar/tar.factor b/extra/tar/tar.factor
index 28913d7141..286ac0183a 100755
--- a/extra/tar/tar.factor
+++ b/extra/tar/tar.factor
@@ -135,7 +135,7 @@ M: unknown-typeflag summary ( obj -- str )
 : typeflag-L ( header -- )
     drop ;
     ! <string-writer> [ read-data-blocks ] keep
-    ! >string [ zero? ] right-trim filename set
+    ! >string [ zero? ] trim-right filename set
     ! filename get tar-prepend-path make-directories ;
 
 ! Multi volume continuation entry