sequences: clarify some stack effect and examlpes in docs

core/sequences/sequences-docs.factor

@@ -269,7 +269,7 @@ HELP: reduce
 
 HELP: reduce-index
 { $values
-     { "seq" sequence } { "identity" object } { "quot" quotation } }
+     { "seq" sequence } { "identity" object } { "quot" { $quotation "( prev elt index -- result )" } } }
 { $description "Combines successive elements of the sequence and their indices binary operations, and outputs the final result. On the first iteration, the three inputs to the quotation are " { $snippet "identity" } ", the first element of the sequence, and its index, 0. On successive iterations, the first input is the result of the previous iteration, the second input is the corresponding element of the sequence, and the third is its index." }
 { $examples { $example "USING: sequences prettyprint math ;"
     "{ 10 50 90 } 0 [ + + ] reduce-index ."
@@ -321,20 +321,20 @@ HELP: map-as
 
 HELP: each-index
 { $values
-     { "seq" sequence } { "quot" quotation } }
+     { "seq" sequence } { "quot" { $quotation "( elt index -- )" } } }
 { $description "Calls the quotation with the element of the sequence and its index on the stack, with the index on the top of the stack." }
-{ $examples { $example "USING: sequences prettyprint math ;"
-"{ 10 20 30 } [ + . ] each-index"
-"10\n21\n32"
+{ $examples { $example "USING: arrays sequences prettyprint ;"
+"{ 10 20 30 } [ 2array . ] each-index"
+"{ 10 0 }\n{ 20 1 }\n{ 30 2 }"
 } } ;
 
 HELP: map-index
 { $values
-  { "seq" sequence } { "quot" quotation } { "newseq" sequence } }
+  { "seq" sequence } { "quot" { $quotation "( elt index -- result )" } } { "newseq" sequence } }
 { $description "Calls the quotation with the element of the sequence and its index on the stack, with the index on the top of the stack. Collects the outputs of the quotation and outputs them in a sequence of the same type as the input sequence." }
-{ $examples { $example "USING: sequences prettyprint math ;"
-"{ 10 20 30 } [ + ] map-index ."
-"{ 10 21 32 }"
+{ $examples { $example "USING: arrays sequences prettyprint ;"
+"{ 10 20 30 } [ 2array ] map-index ."
+"{ { 10 0 } { 20 1 } { 30 2 } }"
 } } ;
 
 HELP: change-nth
@@ -995,8 +995,8 @@ HELP: count
 
 HELP: selector
 { $values
-     { "quot" "a predicate quotation" }
-     { "selector" quotation } { "accum" vector } }
+     { "quot" { $quotation "( elt -- ? )" } }
+     { "selector" { $quotation "( elt -- )" } } { "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 collector if the test yields true. The collector is left on the stack for convenience." }
 { $example "! Find all the even numbers:" "USING: prettyprint sequences math kernel ;"
            "10 iota [ even? ] selector [ each ] dip ."
@@ -1152,7 +1152,7 @@ HELP: replicate
 
 HELP: replicate-as
 { $values
-     { "len" integer } { "quot" quotation } { "exemplar" sequence }
+     { "len" integer } { "quot" { $quotation "( -- elt )" } } { "exemplar" sequence }
      { "newseq" sequence } }
  { $description "Calls the quotation " { $snippet "len" } " times, collecting results into a new sequence of the same type as the exemplar sequence." }
 { $examples 
@@ -1190,7 +1190,7 @@ HELP: virtual@
 
 HELP: 2map-reduce
 { $values
-     { "seq1" sequence } { "seq2" sequence } { "map-quot" quotation } { "reduce-quot" quotation }
+     { "seq1" sequence } { "seq2" sequence } { "map-quot" { $quotation "( elt1 elt2 -- intermediate )" } } { "reduce-quot" { $quotation "( prev intermediate -- result )" } }
      { "result" object } }
  { $description "Calls " { $snippet "map-quot" } " on each pair of elements from " { $snippet "seq1" } " and " { $snippet "seq2" } " and combines the results using " { $snippet "reduce-quot" } " in the same manner as " { $link reduce } ", except that there is no identity element, and the sequence must have a length of at least 1." }
 { $errors "Throws an error if the sequence is empty." }
@@ -1236,7 +1236,7 @@ HELP: collector
 
 HELP: binary-reduce
 { $values
-     { "seq" sequence } { "start" integer } { "quot" quotation }
+     { "seq" sequence } { "start" integer } { "quot" { $quotation "( elt1 elt2 -- newelt )" } }
      { "value" object } }
 { $description "Like " { $link reduce } ", but splits the sequence in half recursively until each sequence is small enough, and calls the quotation on these smaller sequences. If the quotation computes values that depend on the size of their input, such as bignum arithmetic, then this algorithm can be more efficient than using " { $link reduce } "." }
 { $examples "Computing factorial:"
@@ -1247,7 +1247,7 @@ HELP: binary-reduce
 
 HELP: follow
 { $values
-     { "obj" object } { "quot" quotation }
+     { "obj" object } { "quot" { $quotation "( prev -- result/f )" } }
      { "seq" sequence } }
 { $description "Outputs a sequence containing the input object and all of the objects generated by successively feeding the result of the quotation called on the input object to the quotation recursuively. Objects yielded by the quotation are added to the output sequence until the quotation yields " { $link f } ", at which point the recursion terminates." }
 { $examples "Get random numbers until zero is reached:"