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tabatkinstabatkins
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Mostly done with Typed-Calc patch.
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‎css-typed-om/Overview.bs‎

Lines changed: 165 additions & 54 deletions
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@@ -841,30 +841,160 @@ rather than on {{CSSNumericValue}} instances.
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and return the result.
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</div>
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{{CSSNumericValue}}s can be <dfn export for=CSSNumericValue lt="strong type|strongly typed">strongly typed</dfn> to a type
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and/or <dfn export for=CSSNumericValue lt="weak type|weakly typed">weakly typed</dfn> to one or more types,
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or <dfn export for=CSSNumericValue>untyped</dfn>.
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### Numeric Value Typing ### {#numeric-typing}
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Each {{CSSNumericValue}} has an associated <dfn for=CSSNumericValue>type</dfn>,
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which is a combination of an [=ordered map|map=] of [=base types=] to integers,
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and a [=percent hint=].
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The <dfn for=CSSNumericValue lt="base type">base types</dfn> are
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"length",
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"angle",
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"time",
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"frequency",
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"resolution",
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"flex",
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and "percent".
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The ordering of a [=type=]’s entries always matches this [=base type=] ordering.
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The <dfn for=CSSNumericValue>percent hint</dfn>
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is either null or a [=base type=] other than "percent".
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A {{CSSUnitValue}} is [=weakly typed=] to the [=CSS type=] of its {{CSSUnitValue/unit}} internal slot’s value
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if that [=CSS type=] is "percent" or "number".
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It's [=strongly typed=] to that [=CSS type=] otherwise.
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It's never [=untyped=].
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<div algorithm>
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To <dfn local-lt="add | addition">add two types</dfn> |type1| and |type2|,
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perform the following steps:
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1. Replace |type1| with a fresh copy of |type1|,
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and |type2| with a fresh copy of |type2|.
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Let |finalType| be a new [=type=]
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with an initially empty [=ordered map=]
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and an initially null [=percent hint=].
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2.
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<dl class=switch>
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: If both |type1| and |type2| have non-null [=percent hints=]
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with different values
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:: The types can't be added.
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Return failure.
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: If |type1| has a non-null [=percent hint=] |hint| and |type2| doesn't
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:: [=Apply the percent hint=] |hint| to |type2|.
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Vice versa if |type2| has a non-null [=percent hint=] and |type1| doesn't.
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: Otherwise
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:: Continue to the next step.
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</dl>
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3.
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<dl class=switch>
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: If all the [=map/entries=] of |type1| with non-zero values
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are [=map/contained=] in |type2| with the same value,
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and vice-versa
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:: Copy all of |type1|’s [=map/entries=] to |finalType|,
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and then copy all of |type2|’s [=map/entries=] to |finalType|
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that |finalType| doesn't already [=map/contain=].
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Set |finalType|’s [=percent hint=] to |type1|’s [=percent hint=].
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Return |finalType|.
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: If |type1| and/or |type2| [=map/contain=] "percent" with a non-zero value,
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and |type1| and/or |type2| [=map/contain=] a key *other than* "percent" with a non-zero value
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:: For each [=base type=] other than "percent" |hint|:
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1. Provisionally [=apply the percent hint=] |hint| to both |type1| and |type2|.
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2. If, afterwards, all the [=map/entries=] of |type1| with non-zero values
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are [=map/contained=] in |type2| with the same value,
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and vice versa,
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then copy all of |type1|’s [=map/entries=] to |finalType|,
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and then copy all of |type2|’s [=map/entries=] to |finalType|
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that |finalType| doesn't already [=map/contain=].
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Set |finalType|’s [=percent hint=] to |hint|.
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Return |finalType|.
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3. Otherwise, revert |type1| and |type2| to their state at the start of this loop.
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If the loop finishes without returning |finalType|,
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then the types can't be added.
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Return failure.
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Note: You can shortcut this in some cases
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by just checking the sum of all the [=map/values=]
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of |type1| vs |type2|.
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If the sums are different,
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the types can't be added.
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: Otherwise
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:: The types can't be added.
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Return failure.
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</dl>
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</div>
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<div algorithm>
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To <dfn>apply the percent hint</dfn> |hint| to a |type|,
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perform the following steps:
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1. If |type| doesn't [=map/contain=] |hint|, set |type|[|hint|] to 0.
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2. If |type| [=map/contains=] "percent", add |type|["percent"] to |type|[|hint|],
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then set |type|["percent"] to 0.
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4. Set |type|’s [=percent hint=] to |hint|.
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</div>
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A {{CSSMathSum}}, {{CSSMathProduct}}, {{CSSMathMin}}, or {{CSSMathMax}}
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is [=strongly typed=]
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if any of the values in its {{CSSMathSum/values}} internal slot
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are [=strongly typed=],
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to that same [=strong type=].
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It's [=weakly typed=] to the union of the [=weak types=]
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of all of the values in its {{CSSMathSum/values}} internal slot.
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It's [=untyped=] if its {{CSSMathSum/values}} internal slot [=list/is empty=].
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<div algorithm>
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To <dfn for=CSSNumericValue local-lt="multiply | multiplication">multiply two types</dfn> |type1| and |type2|,
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perform the following steps:
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1. Replace |type1| with a fresh copy of |type1|,
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and |type2| with a fresh copy of |type2|.
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Let |finalType| be a new [=type=]
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with an initially empty [=ordered map=]
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and an initially null [=percent hint=].
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2. If both |type1| and |type2| have non-null [=percent hints=]
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with different values,
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the types can't be multiplied.
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Return failure.
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3. If |type1| has a non-null [=percent hint=] |hint| and |type2| doesn't,
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[=apply the percent hint=] |hint| to |type2|.
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A {{CSSMathNegate}} or {{CSSMathInvert}}
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is [=strongly typed=],
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[=weakly typed=],
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or [=untyped=]
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identically to the value in its {{CSSMathNegate/value}} internal slot.
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Vice versa if |type2| has a non-null [=percent hint=] and |type1| doesn't.
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4. Copy all of |type1|’s [=map/entries=] to |finalType|,
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then [=map/for each=] |baseType| → |power| of |type2|:
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1. If |finalType|[|baseType|] [=map/exists=],
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increment its value by |power|.
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2. Otherwise, set |finalType|[|baseType|] to |power|.
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Set |finalType|’s [=percent hint=] to |type1|’s [=percent hint=].
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5. Return |finalType|.
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</div>
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A [=type=] is said to <dfn for=CSSNumericValue>match</dfn> a CSS production in some circumstances:
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* A [=type=] matches <<length>>
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if its only non-zero [=map/entry=] is «[ "length" → 1 ]»
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and its [=percent hint=] is null.
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Similarly for <<angle>>, <<time>>, <<frequency>>, <<resolution>>, and <<flex>>.
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* A [=type=] matches <<percentage>>
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if its only non-zero [=map/entry=] is «[ "percent" → 1 ]».
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* A [=type=] matches <<length-percentage>>
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if its only non-zero [=map/entry=] is either «[ "length" → 1 ]» or «[ "percentage" → 1 ]»
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Same for <<angle-percentage>>, <<time-percentage>>, etc.
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* A [=type=] matches <<number>>
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if it has no non-zero [=map/entries=]
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and its [=percent hint=] is null.
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* A [=type=] matches <<number-percentage>>
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if it has no non-zero [=map/entries=],
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or its only non-zero [=map/entry=] is «[ "percentage" → 1 ]».
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Many specifications use ''[ <<length>> | <<percentage>> ]''
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instead of ''<<length-percentage>>'' in their grammar,
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and specify in prose that the <<length>> and <<percentage>> can be combined.
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For the purposes of [=matching=],
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these cases should be treated as <<length-percentage>>.
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Similarly for <<angle-percentage>>, etc.
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@@ -937,40 +1067,37 @@ are represented as {{CSSUnitValue}}s.
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<div algorithm="CSSUnitValue.type">
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The <dfn attribute for=CSSUnitValue>type</dfn> attribute of a {{CSSUnitValue}} |this| must,
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on reading,
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return the [=CSS type=] of |this|’s {{CSSUnitValue/unit}} internal slot’s value.
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Issue: Figure out how we're exposing types. This should probably move up to the superclass, then.
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</div>
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<div algorithm="CSS type of a unit">
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The <dfn>CSS type</dfn> of a string |unit| is:
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The [=type=] of a {{CSSUnitValue}}
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depends on its {{CSSUnitValue/unit}} as follows:
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<dl class=switch>
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: |unit| is "number"
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:: "number"
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:: [=type=] is «[ ]» (empty map)
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: |unit| is "percent"
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:: "percent"
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:: [=type=] is «[ "percent" → 1 ]»
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: |unit| is a <<length>> unit
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:: "length"
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:: [=type=] is «[ "length" → 1 ]»
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: |unit| is an <<angle>> unit
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:: "angle"
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:: [=type=] is «[ "angle" → 1 ]»
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: |unit| is a <<time>> unit
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:: "time"
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:: [=type=] is «[ "time" → 1 ]»
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: |unit| is a <<frequency>> unit
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:: "frequency"
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:: [=type=] is «[ "frequence" → 1 ]»
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: |unit| is a <<resolution>> unit
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:: "resolution"
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:: [=type=] is «[ "resolution" → 1 ]»
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: |unit| is a <<flex>> unit
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:: "flex"
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:: [=type=] is «[ "flex" → 1 ]»
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: anything else
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:: the string does not have a [=CSS type=]
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</dl>
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</div>
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A {{CSSUnitValue}} matches a CSS type production,
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such as <<number>> or <<length>>,
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if its equivalent CSS value
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(with the same value and unit,
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or similar with "number" and "percent")
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matches that production.
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In all cases, the [=percent hint=] of the [=type=] is null.
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</div>
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<div algorithm>
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When asked to <dfn export local-lt="new unit value">create a new unit value</dfn>
@@ -1111,24 +1238,8 @@ of all the "math" operations.
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The <dfn attribute for="CSSMathValue, CSSMathSum, CSSMathProduct, CSSMathMin, CSSMathMax, CSSMathNegate, CSSMathInvert">type</dfn> attribute
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of a {{CSSMathValue}} |this| must,
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on reading,
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perform the following steps:
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1. Let |types| initially be an empty [=ordered set=].
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2. If |this| has a [=strong type=],
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[=set/append=] its [=strong type=] to |types|.
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3. If |this| has the "percent" [=weak type=],
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[=set/append=] "percent" to |types|.
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4. If |this| has the "number" [=weak type=],
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[=set/append=] "number" to |types|.
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5. Return the concatenation of the strings in |types|,
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each separated by a U+002D HYPHEN-MINUS (-) character.
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1130-
Note: This implies that if |this| is [=untyped=],
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this attribute returns the empty string.
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Issue: Figure out how we're outputting .type
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</div>
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<div algorithm="CSSMathSum(...args)">

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