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First draft of real switch statements for CoffeeScript switch statements.

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Jeremy Ashkenas
2010-09-15 23:46:01 -04:00
parent 60f80e2698
commit d8465ce767
6 changed files with 128 additions and 38 deletions
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18
src/grammar.coffee
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@@ -485,26 +485,22 @@ grammar =
o "IN Expression BY Expression WHEN Expression", -> source: $2, step: $4, guard: $6
]
# The CoffeeScript switch/when/else block replaces the JavaScript
# switch/case/default by compiling into an if-else chain.
Switch: [
o "SWITCH Expression INDENT Whens OUTDENT", -> $4.switchesOver $2
o "SWITCH Expression INDENT Whens ELSE Block OUTDENT", -> $4.switchesOver($2).addElse $6, true
o "SWITCH INDENT Whens OUTDENT", -> $3
o "SWITCH INDENT Whens ELSE Block OUTDENT", -> $3.addElse $5, true
o "SWITCH Expression INDENT Whens OUTDENT", -> new SwitchNode $2, $4
o "SWITCH Expression INDENT Whens ELSE Block OUTDENT", -> new SwitchNode $2, $4, $6
o "SWITCH INDENT Whens OUTDENT", -> new SwitchNode null, $3
o "SWITCH INDENT Whens ELSE Block OUTDENT", -> new SwitchNode null, $3, $5
]
# The inner list of whens is left recursive. At code-generation time, the
# IfNode will rewrite them into a proper chain.
Whens: [
o "When"
o "Whens When", -> $1.addElse $2
o "Whens When", -> $1.concat $2
]
# An individual **When** clause, with action.
When: [
o "LEADING_WHEN SimpleArgs Block", -> new IfNode $2, $3, statement: true
o "LEADING_WHEN SimpleArgs Block TERMINATOR", -> new IfNode $2, $3, statement: true
o "LEADING_WHEN SimpleArgs Block", -> [[$2, $3]]
o "LEADING_WHEN SimpleArgs Block TERMINATOR", -> [[$2, $3]]
]
# The most basic form of *if* is a condition and an action. The following