Mercurial > repos > other > SevenLanguagesInSevenWeeks
comparison 2-Io/day3-DSL.io @ 43:d2764720ea17
Add the Day 3 'Domain Specific Language'
| author | IBBoard <dev@ibboard.co.uk> |
|---|---|
| date | Mon, 18 Sep 2017 20:45:32 +0100 |
| parents | |
| children | 6347bacb3be7 |
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| 42:54608c26bda2 | 43:d2764720ea17 |
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| 1 # Creating a simple "domain-specific language" | |
| 2 # (Except it's not really - it's just a little extension to support | |
| 3 # the "{ key:value[, key:value[…]] }" format of specifying dictionaries) | |
| 4 | |
| 5 # Because this is a string then we can do it at any time! | |
| 6 OperatorTable addAssignOperator(":", "atPutThing") | |
| 7 | |
| 8 # curlyBrackets is an automatically invoked function from the parser whenever | |
| 9 # it encounters curly brackets. | |
| 10 # This is hidden black magic that you need to know about to override it. | |
| 11 # It appears to call the method for all of the content within the brackets. | |
| 12 curlyBrackets := method( | |
| 13 map := Map clone | |
| 14 call message arguments foreach(arg, | |
| 15 map doMessage(arg) | |
| 16 ) | |
| 17 map | |
| 18 ) | |
| 19 | |
| 20 Map atPutThing := method( | |
| 21 self atPut( | |
| 22 call evalArgAt(0) asMutable removePrefix("\"") removeSuffix("\""), | |
| 23 call evalArgAt(1) | |
| 24 ) | |
| 25 ) | |
| 26 | |
| 27 the_string := "{ | |
| 28 \"foo\": \"12345\", | |
| 29 \"bar\": \"7890\" | |
| 30 }" | |
| 31 | |
| 32 phoneNumbers := doString(the_string) | |
| 33 phoneNumbers keys println | |
| 34 phoneNumbers values println | |
| 35 | |
| 36 # But presumably this will break, because there's no "atPutThing" method | |
| 37 a := 1 | |
| 38 b := 5 | |
| 39 range := a : b | |
| 40 # Yep - "Exception: Number does not respond to ':'" | |
| 41 # So you've got to be careful for reusable operators |