prepare release 4.2.4

[nominatim.git] / docs / customize / Tokenizers.md

diff --git a/docs/customize/Tokenizers.md b/docs/customize/Tokenizers.md
index d849eb48c0d457c7c57b27e2807ff55675e2fa33..58606c29d0176822ce3364324520b34634a5e242 100644 (file)
--- a/docs/customize/Tokenizers.md
+++ b/docs/customize/Tokenizers.md
@@ -19,7 +19,22 @@ they can be configured.
 
 The legacy tokenizer implements the analysis algorithms of older Nominatim
 versions. It uses a special Postgresql module to normalize names and queries.
-This tokenizer is currently the default.
+This tokenizer is automatically installed and used when upgrading an older
+database. It should not be used for new installations anymore.
+
+### Compiling the PostgreSQL module
+
+The tokeinzer needs a special C module for PostgreSQL which is not compiled
+by default. If you need the legacy tokenizer, compile Nominatim as follows:
+
+```
+mkdir build
+cd build
+cmake -DBUILD_MODULE=on
+make
+```
+
+### Enabling the tokenizer
 
 To enable the tokenizer add the following line to your project configuration:
 
@@ -47,6 +62,7 @@ normalization functions are hard-coded.
 The ICU tokenizer uses the [ICU library](http://site.icu-project.org/) to
 normalize names and queries. It also offers configurable decomposition and
 abbreviation handling.
+This tokenizer is currently the default.
 
 To enable the tokenizer add the following line to your project configuration:
 
@@ -189,6 +205,23 @@ The following is a list of sanitizers that are shipped with Nominatim.
     rendering:
         heading_level: 6
 
+##### clean-postcodes
+
+::: nominatim.tokenizer.sanitizers.clean_postcodes
+    selection:
+        members: False
+    rendering:
+        heading_level: 6
+
+##### clean-tiger-tags
+
+::: nominatim.tokenizer.sanitizers.clean_tiger_tags
+    selection:
+        members: False
+    rendering:
+        heading_level: 6
+
+
 
 #### Token Analysis
 
@@ -206,8 +239,12 @@ by a sanitizer (see for example the
 The token-analysis section contains the list of configured analyzers. Each
 analyzer must have an `id` parameter that uniquely identifies the analyzer.
 The only exception is the default analyzer that is used when no special
-analyzer was selected. There is one special id '@housenumber'. If an analyzer
-with that name is present, it is used for normalization of house numbers.
+analyzer was selected. There are analysers with special ids:
+
+ * '@housenumber'. If an analyzer with that name is present, it is used
+   for normalization of house numbers.
+ * '@potcode'. If an analyzer with that name is present, it is used
+   for normalization of postcodes.
 
 Different analyzer implementations may exist. To select the implementation,
 the `analyzer` parameter must be set. The different implementations are
@@ -340,6 +377,14 @@ house numbers of the form '3 a', '3A', '3-A' etc. are all considered equivalent.
 
 The analyzer cannot be customized.
 
+##### Postcode token analyzer
+
+The analyzer `postcodes` is pupose-made to analyze postcodes. It supports
+a 'lookup' varaint of the token, which produces variants with optional
+spaces. Use together with the clean-postcodes sanitizer.
+
+The analyzer cannot be customized.
+
 ### Reconfiguration
 
 Changing the configuration after the import is currently not possible, although