Moving from Microsoft.Recognizers.Text

Microsoft.Recognizers.Text finds numbers, units, currency, sequences and date/time expressions and returns ModelResult values. OneNLP's recognizers do the same job with one engine and rules kept as data per language. This page maps the calls. It is written from the package's published usage and from running version 1.8.13 as a black box on our own gold sentences (recognizer-gold.md); nothing comes from its source or its spec files. There is no shim.

At a glance

Which call becomes which

Before and after

Recognizers.Text:

using Microsoft.Recognizers.Text;
using Microsoft.Recognizers.Text.DateTime;
using Microsoft.Recognizers.Text.NumberWithUnit;
using Microsoft.Recognizers.Text.Sequence;
 
var reference = new DateTime(2026, 3, 18, 10, 30, 0);
string text = "Pay $20 to bob@example.com by 5 March 2026, or within two weeks.";
 
var money = NumberWithUnitRecognizer.RecognizeCurrency(text, Culture.English);
var email = SequenceRecognizer.RecognizeEmail(text, Culture.English);
var dates = DateTimeRecognizer.RecognizeDateTime(text, Culture.English, DateTimeOptions.None, reference);
foreach (var r in money.Concat(email).Concat(dates))
{
    Console.WriteLine($"{r.TypeName} [{r.Start},{r.End}] {r.Text}");      // End is inclusive
}

OneNLP (samples/OneNlp.Samples/MigrationSamples.cs, which builds and runs):

Recognizer english = Recognizer.English;                              // Recognizer.For(Language.French), ... for the other nine
DateTimeOffset reference = new(2026, 3, 18, 10, 30, 0, TimeSpan.Zero);
 
foreach (Recognition r in english.Recognize("Pay $20 to bob@example.com by 5 March 2026, or within two weeks.", new RecognitionContext(reference)))
{
    string detail = r switch
    {
        Quantity q => $"{q.Kind} {q.Value} {q.Unit ?? q.Currency}",     // ModelResult.Resolution["value"], ["unit"]
        TemporalMatch t => $"{t.Kind} {t.Value} {t.Range?.Start:yyyy-MM-dd}", // Resolution["values"][..]["timex"], ["start"], ["end"]
        SequenceMatch s => $"{s.Kind}",
        _ => string.Empty,
    };
    Console.WriteLine($"{r.Label,-10} [{r.Start},{r.End}) {r.Text}  {detail}");   // TypeName, Start, End (inclusive in the old library)
}

Differences that matter when you port

• Spans do not overlap. One call returns every type in text order, and where two readings cover the same characters the engine keeps one (recognizers.md, "Overlaps"). Recognizers.Text returns each model's results separately, so the same characters can appear as a number and as part of a date.
• Ranges end where they say. A DateRange has an inclusive Start and an exclusive End: from April 6 to April 10 ends at the start of April 11. Recognizers.Text states the end of such day ranges as the end day itself. Both conventions are named in recognizer-gold.md.
• Several candidates. For an ambiguous expression Recognizers.Text lists several values (past and future Friday, am and pm). OneNLP resolves to one, by rules written in recognizers.md (a bare weekday is the first such day on or after the reference day; next Friday is Friday of next week).
• Time zones are explicit. A stated zone (PST, UTC+2, a trailing Z) is kept in Value, UtcOffset and the offset of Range. There is no time zone database, so no daylight-saving arithmetic.
• Approximate expressions (spring 2021, early 2021, late 2023) resolve to a range with a granularity and an Approximate flag.
• Region. RecognitionContext.Region (us or gb) picks the order of numeric dates and the holidays.
• Rules are data. The words, symbols, units, currencies, holidays and patterns of a language are rule files, not code; the grammar that combines them is code (recognizers.md, "Rule data" says where the line falls). Recognizer.FromFiles(...) loads rules from your own files, so you can add a unit, a currency or a holiday without a new build.
• Values are exact. Quantity.Value is a decimal; money does not round-trip through double.

On our hand-labelled test sets, in each of eight languages, every type is within noise of or ahead of Recognizers.Text, and the engine is faster; the rows are in results-table.md and results.md.