Grammar support for Russian way names #102
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| ## Grammar support | ||
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| Many languages - all Slavic (Russian, Ukrainian, Polish, Bulgarian, etc), Finnic (Finnish, Estonian) and others - have [grammatical case feature](https://en.wikipedia.org/wiki/Grammatical_case) that could be supported in OSRM Text Instructions too. | ||
| Originally street names are being inserted into instructions as they're in OSM map - in [nominative case](https://en.wikipedia.org/wiki/Nominative_case). | ||
| To be grammatically correct, street names should be changed according to target language rules and instruction context before insertion. | ||
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| Actually grammatical case applying is not the simple and obvious task due to real-life languages complexity. | ||
| It even looks so hard so, for example, all known native Russian navigation systems don't speak street names in their pronounceable route instructions at all. | ||
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| But fortunately street names have restricted lexicon and naming rules and so this task could be relatively easily solved for this particular case. | ||
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| ### Implementation details | ||
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| The quite universal and simplier solution is the changing street names with the prepared set of regular expressions grouped by required grammatical case. | ||
| The required grammatical case should be specified right in instruction's substitution variables: | ||
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| - `{way_name}` and `{rotary_name}` variables in translated instructions should be appended with required grammar case name after colon: `{way_name:accusative}` for example | ||
| - [languages/grammar](languages/grammar/) folder should contain language-specific JSON file with regular expressions for specified grammar case: | ||
| ```json | ||
| { | ||
| "v5": { | ||
| "accusative": [ | ||
| ["^ (\\S+)ая-(\\S+)ая [Уу]лица ", " $1ую-$2ую улицу "], | ||
| ["^ (\\S+)ая [Уу]лица ", " $1ую улицу "], | ||
| ... | ||
| ``` | ||
| - All such JSON files should be registered in common [languages.js](languages.js) | ||
| - Instruction text formatter ([index.js](index.js) in this module) should: | ||
| - check `{way_name}` and `{rotary_name}` variables for optional grammar case after colon: `{way_name:accusative}` | ||
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There was a problem hiding this comment. I like this syntax – it leaves open the possibility of additional transformations like capitalization, which could replace the "capitalizeFirstLetter" meta property currently set on some localizations. |
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| - find appropriate regular expressions block for target language and specified grammar case | ||
| - call standard [string replace with regular expression](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace) for each expression in block passing result from previous call to the next; the first call should enclose original street name with whitespaces to make parsing words in names a bit simplier. | ||
| - Strings replacement with regular expression is available in almost all other programming language and so this should not be the problem for other code used OSRM Text Instructions' data only. | ||
| - If there is no regular expression matched source name (that's for names from foreign country for example), original name is returned without changes. This is also expected behavior of standard [string replace with regular expression](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace). And the same behavior is expected in case of missing grammar JSON file or grammar case inside it. | ||
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| ### Example | ||
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| Russian _"Большая Монетная улица"_ street from St Petersburg (_Big Monetary Street_ in rough translation) after processing with [Russian grammar rules](languages/grammar/ru.json) will look in following instructions as: | ||
| - _"Turn left onto `{way_name}`"_ => `ru`:_"Поверните налево на `{way_name:accusative}`"_ => _"Поверните налево на Большую Монетную улицу"_ | ||
| - _"Continue onto `{way_name}`"_ => `ru`:_"Продолжите движение по `{way_name:dative}`"_ => _"Продолжите движение по Большой Монетной улице"_ | ||
| - _"Make a U-turn onto `{way_name}` at the end of the road"_ => `ru`:_"Развернитесь в конце `{way_name:genitive}`"_ => _"Развернитесь в конце Большой Монетной улицы"_ | ||
| - _"Make a U-turn onto `{way_name}`"_ => `ru`:_"Развернитесь на `{way_name:prepositional}`"_ => _"Развернитесь на Большой Монетной улице"_ | ||
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| ### Design goals | ||
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| - __Cross platform__ - uses the same data-driven approach as OSRM Text Instructions | ||
| - __Test suite__ - has [prepared test](test/grammar_tests.js) to check available expressions automatically and has easily extendable language-specific names testing pattern | ||
| - __Customization__ - could be easily extended for other languages with adding new regular expressions blocks into [grammar support](languages/grammar/) folder and modifying `{way_name}` and other variables in translated instructions only with necessary grammatical case labels | ||
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| ### Notes | ||
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| - Russian regular expressions are based on [Garmin Russian TTS voices update](https://github.com/yuryleb/garmin-russian-tts-voices) project; see [file with regular expressions to apply to source text before pronouncing by TTS](https://github.com/yuryleb/garmin-russian-tts-voices/blob/master/src/Pycckuu__Milena%202.10/RULESET.TXT). | ||
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There was a problem hiding this comment. Thank you for dedicating this rule set to the public domain! |
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| - There is another grammar-supporting module - [jquery.i18n](https://github.com/wikimedia/jquery.i18n) - but unfortunately it has very poor implementation in part of grammatical case applying and is supposed to work with single words only. | ||
| - Actually it would be great to get street names also in target language not from default OSM `name` only - there are several multi-lingual countries supporting several `name:<lang>` names for streets. But this the subject to address to [OSRM engine](https://github.com/Project-OSRM/osrm-backend) first. | ||
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There was a problem hiding this comment. This is a good idea – please file an issue in osrm-backend. |
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| @@ -1,5 +1,6 @@ | ||
| var languages = require('./languages'); | ||
| var instructions = languages.instructions; | ||
| var grammars = languages.grammars; | ||
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| module.exports = function(version, _options) { | ||
| var opts = {}; | ||
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@@ -104,7 +105,6 @@ module.exports = function(version, _options) { | |
| switch (type) { | ||
| case 'use lane': | ||
| laneInstruction = instructions[language][version].constants.lanes[this.laneConfig(step)]; | ||
| if (!laneInstruction) { | ||
| // If the lane combination is not found, default to continue straight | ||
| instructionObject = instructions[language][version]['use lane'].no_lanes; | ||
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@@ -199,10 +199,37 @@ module.exports = function(version, _options) { | |
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| return this.tokenize(language, instruction, replaceTokens); | ||
| }, | ||
| grammarize: function(language, name, grammar) { | ||
| // Process way/rotary name with applying grammar rules if any | ||
| if (name && grammar && grammars && grammars[language] && grammars[language][version]) { | ||
| var rules = grammars[language][version][grammar]; | ||
| if (rules) { | ||
| // Pass original name to rules' regular expressions enclosed with spaces for simplier parsing | ||
| var n = ' ' + name + ' '; | ||
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There was a problem hiding this comment. It's currently possible for clients to manipulate a step's name before compilation. For example, the Mapbox Directions API currently inserts SSML markup around numbers within the name so that speech synthesizers pronounce them more casually. I think that could potentially interfere with this feature. That would be a good argument for implementing #52, so that clients can reliably manipulate the name after grammaticalization. There was a problem hiding this comment. No problem, if clients will not damage There was a problem hiding this comment. But actually it's no problem, even if Mapbox will catch and replace There was a problem hiding this comment. I’m referring to a JavaScript port of mapbox/mapbox-navigation-ios#552 for the Directions API’s (not yet documented) I’ll be the first to admit it’s a hack, but I wanted to point this out because clients may be inclined to do similar things to the value of /cc @allierowan |
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| var flags = grammars[language].meta.regExpFlags || ''; | ||
| rules.forEach(function(rule) { | ||
| var re = new RegExp(rule[0], flags); | ||
| n = n.replace(re, rule[1]); | ||
| }); | ||
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| return n.trim(); | ||
| } | ||
| } | ||
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| return name; | ||
| }, | ||
| tokenize: function(language, instruction, tokens) { | ||
| // Keep this function context to use in inline function below (no arrow functions in ES4) | ||
| var that = this; | ||
| var output = instruction.replace(/\{(\w+):?(\w+)?\}/g, function(token, tag, grammar) { | ||
| var name = tokens[tag]; | ||
| if (typeof name !== 'undefined') { | ||
| return that.grammarize(language, name, grammar); | ||
| } | ||
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| // Return unknown token unchanged | ||
| return token; | ||
| }) | ||
| .replace(/ {2}/g, ' '); // remove excess spaces | ||
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| if (instructions[language].meta.capitalizeFirstLetter) { | ||
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Are the various cases always regular and easy to determine from the nominative case? I noticed a few features have been tagged
name:dativein OpenStreetMap – would it be desirable or necessary for OSRM to pass such tags along to OSRM Text Instructions?There was a problem hiding this comment.
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IMHO it's not deal of OSM - it's impossible to store all case variants in all languages for each name. Perhaps CLDR will be the better place (if will 😉 )