github/coffeescript
1
1
Fork 0
mirror of https://github.com/jashkenas/coffeescript.git synced 2026-01-14 17:27:59 -05:00
Code Issues Packages Projects Releases Wiki Activity

enhancements to range comprehensions, back to being safe -- and usable downwards without a 'by' clause, and optimized when working with integer literals.

Browse Source
This commit is contained in:
Jeremy Ashkenas
2010-07-17 18:45:29 -04:00
parent 96f076983e
commit 5a34f53689
7 changed files with 88 additions and 53 deletions
Download Patch File Download Diff File Expand all files Collapse all files

50
src/nodes.coffee
View File

@@ -531,41 +531,57 @@ exports.RangeNode: class RangeNode extends BaseNode
@from: from
@to: to
@exclusive: !!exclusive
@equals: if @exclusive then '' else '='
# Compiles the range's source variables -- where it starts and where it ends.
# But only if they need to be cached to avoid double evaluation.
compileVariables: (o) ->
[@from, @fromVar]: @from.compileReference o
[@to, @toVar]: @to.compileReference o
[@from, @fromVar]: @from.compileReference o, {precompile: yes}
[@to, @toVar]: @to.compileReference o, {precompile: yes}
[@fromNum, @toNum]: [@fromVar.match(SIMPLENUM), @toVar.match(SIMPLENUM)]
parts: []
parts.push @from.compile o if @from isnt @fromVar
parts.push @to.compile o if @to isnt @toVar
if parts.length then "${parts.join('; ')};" else ''
parts.push @from if @from isnt @fromVar
parts.push @to if @to isnt @toVar
if parts.length then "${parts.join('; ')}; " else ''
# When compiled normally, the range returns the contents of the *for loop*
# needed to iterate over the values in the range. Used by comprehensions.
compileNode: (o) ->
return @compileArray(o) unless o.index
return @compileArray(o) unless o.index
return @compileSimple(o) if @fromNum and @toNum
idx: del o, 'index'
step: del o, 'step'
vars: "$idx = ${@fromVar.compile(o)}"
step: if step then step.compile(o) else '1'
equals: if @exclusive then '' else '='
op: if starts(step, '-') then ">$equals" else "<$equals"
"$vars; ${idx} $op ${@toVar.compile(o)}; $idx += $step"
vars: "$idx = $@fromVar"
intro: "($@fromVar <= $@toVar ? $idx"
compare: "$intro <$@equals $@toVar : $idx >$@equals $@toVar)"
stepPart: if step then step.compile(o) else '1'
incr: if step then "$idx += $stepPart" else "$intro += $stepPart : $idx -= $stepPart)"
"$vars; $compare; $incr"
# Compile a simple range comprehension, with integers.
compileSimple: (o) ->
[from, to]: [parseInt(@fromNum, 10), parseInt(@toNum, 10)]
idx: del o, 'index'
step: del o, 'step'
step: and "$idx += ${step.compile(o)}"
if from <= to
"$idx = $from; $idx <$@equals $to; ${step or "$idx++"}"
else
"$idx = $from; $idx >$@equals $to; ${step or "$idx--"}"
# When used as a value, expand the range into the equivalent array.
compileArray: (o) ->
idt: @idt 1
vars: @compileVariables(merge(o, {indent: idt}))
equals: if @exclusive then '' else '='
from: @fromVar.compile o
to: @toVar.compile o
result: o.scope.freeVariable()
i: o.scope.freeVariable()
clause: "$from <= $to ?"
pre: "\n${idt}${result} = []; ${vars}"
body: "var $i = $from; $clause $i <$equals $to : $i >$equals $to; $clause $i += 1 : $i -= 1"
if @fromNum and @toNum
o.index: i
body: @compileSimple o
else
clause: "$@fromVar <= $@toVar ?"
body: "var $i = $@fromVar; $clause $i <$@equals $@toVar : $i >$@equals $@toVar; $clause $i += 1 : $i -= 1"
post: "{ ${result}.push($i) };\n${idt}return $result;\n$o.indent"
"(function(){${pre}\n${idt}for ($body)$post}).call(this)"
@@ -1266,7 +1282,6 @@ exports.ForNode: class ForNode extends BaseNode
body: Expressions.wrap([@body])
if range
sourcePart: source.compileVariables(o)
sourcePart: + "\n$o.indent" if sourcePart
forPart: source.compile merge o, {index: ivar, step: @step}
else
svar: scope.freeVariable()
@@ -1492,6 +1507,7 @@ DOUBLE_PARENS: /\(\(([^\(\)\n]*)\)\)/g
# Keep these identifier regexes in sync with the Lexer.
IDENTIFIER: /^[a-zA-Z\$_](\w|\$)*$/
NUMBER : /^(((\b0(x|X)[0-9a-fA-F]+)|((\b[0-9]+(\.[0-9]+)?|\.[0-9]+)(e[+\-]?[0-9]+)?)))\b$/i
SIMPLENUM : /^-?\d+/
# Is a literal value a string?
IS_STRING: /^['"]/