java.lang.Object
- com.squarespace.cldrengine.message.MessagePatternParser

```
public class MessagePatternParser
extends java.lang.Object
```
Hand-implemented parser for ICU message format. Designed to be compact and fast vs. other implementations. The parser produces an instruction tree which can be cached for repeated use, and is intended to be evaluated by a separate engine. Note: The 'choice' formatter is not implemented since it is deprecated. See ICU docs for details on syntax: https://unicode-org.github.io/icu-docs/apidoc/released/icu4j/com/ibm/icu/text/MessageFormat.html Rationale The decision to hand-implement the parser was for 2 reasons: 1. Avoiding extra runtime dependencies (parser generators, e.g. pegjs, etc) 2. Provide control over the memory allocation, garbage generation, and other aspects that impact parser performance. A major consideration is size of the resulting parser code. The OpenJS project 'messageformat-parser' which is generated by Peg.js is 30kB minified. It also requires other dependencies for the plural calculations, where this is already supported in our library via @phensley/plurals See: https://unpkg.com/messageformat-parser/parser.js

Constructor Summary

Constructors
Constructor	Description
`MessagePatternParser(java.util.Collection<java.lang.String> formatters, java.lang.String str, boolean disableEscapes)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected MessageCode`	`flatten(java.util.List<MessageCode> n)`
`MessageCode`	`inner(MessageMatcher.State r)`
`MessageCode`	`outer(MessageMatcher.State r, java.lang.Object argsub)`
`MessageCode`	`parse()`
`protected MessageCode`	`plural(java.util.List<java.lang.Object> args, PluralNumberType type, MessageMatcher.State r)`	Parse a plural instruction.
`protected int`	`seek(int i, int j)`	Seek to the matching '}' character at the same nesting level, skipping over any apostrophes.
`protected MessageCode`	`select(java.util.List<java.lang.Object> args, MessageMatcher.State r)`	Parse a select instruction.
`protected MessageCode`	`simple(java.util.List<java.lang.Object> args, java.lang.String name, MessageMatcher.State r)`	Simple single-argument formatter with zero or more options.
`protected MessageCode`	`tag(MessageMatcher.State r, java.lang.Object argsub)`	Parse a nested tag sequence '{' ...
`protected MessageCode`	`textarg(java.lang.String s, java.lang.Object argsub)`	Emit a text node, performing argument substitution for all occurrences of the '#' character.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MessagePatternParser

public MessagePatternParser(java.util.Collection<java.lang.String> formatters,
                            java.lang.String str,
                            boolean disableEscapes)

Method Detail

parse
```
public MessageCode parse()
```

outer

public MessageCode outer(MessageMatcher.State r,
                         java.lang.Object argsub)

inner

public MessageCode inner(MessageMatcher.State r)

tag

protected MessageCode tag(MessageMatcher.State r,
                          java.lang.Object argsub)

Parse a nested tag sequence '{' ... '}'

plural

protected MessageCode plural(java.util.List<java.lang.Object> args,
                             PluralNumberType type,
                             MessageMatcher.State r)

Parse a plural instruction.

select

protected MessageCode select(java.util.List<java.lang.Object> args,
                             MessageMatcher.State r)

Parse a select instruction.

simple

protected MessageCode simple(java.util.List<java.lang.Object> args,
                             java.lang.String name,
                             MessageMatcher.State r)

Simple single-argument formatter with zero or more options.

seek
```
protected int seek(int i,
                   int j)
```
Seek to the matching '}' character at the same nesting level, skipping over any apostrophes. This adds some redundant scanning of the string but simplifies some of the parsing logic in other areas. It ensures we're always dealing with a well-formed tag where all '{' have a corresponding '}'.

textarg

protected MessageCode textarg(java.lang.String s,
                              java.lang.Object argsub)

Emit a text node, performing argument substitution for all occurrences of the '#' character.

flatten

protected MessageCode flatten(java.util.List<MessageCode> n)

Class MessagePatternParser