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REPL Console Customization

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mattirn edited this page Jan 23, 2021 · 9 revisions

REPL console is customized by using init script, config files and console variables. In order to work correctly some JLine commands and configurations require that application ConfigurationPath has been set in application startup.

objectHighlight

Console

Init script

Application console enviroment is initialized using SystemRegistry method initialize(File initScript). Initialization script can be used to create:

  1. custom pipes
  2. command and pipe aliases
  3. custom widgets and key bindings
  4. prnt command default options and highlight rules

An initialization script example, see REPL demo init.jline.

Variables

PATH

A list of directories from where ConsoleEngine is searching scripts.

CONSOLE_OPTIONS

A map that contains console options:

  • HELP_COLORS string variable that defines command help highlighting.
  • LS_COLORS string variable that defines file names highlighting.
  • PRNT_COLORS string variable that defines prnt command output highlighting.
  • docs a map<regex, url>. Command doc configuration. If command parameter full class name matches regex the javadoc url will be constructed and open in the browser.
  • maxValueNames maximum number of pipeline names that are persisted so that they can be reused in later sessions. Pipeline names are used by PipelineCompleter to offer tab completions.
  • no-splittedOutput as a default ConsoleEngine will split multiline command output to the String array. This will facilitate the use of pipe operations.
  • trace ConsoleEngine trace level. Valid values: 0 - 2. Default value 0 (no trace).

prnt command

NANORC

The command prnt can use Nano SyntaxHighlighter to highlight object output. The nanorc configuration file is searched from

  1. ConfigurationPath: jnanorc file is first looked from the user-config path, if the file is not found then it is looked from the application-config path.
  2. NANORC console variable: full name of the nanorc file
  3. /etc/nanorc

PRNT_OPTIONS

A map that contains prnt command default options.

In a console the evaluated command result is converted to the Map<String,Object> or in a case of collection to the List<Map<String,Object>> before printing it to the console. The collection result is printed out as a table if the collection map key sets match sufficiently well with each other. If the collection map key sets differ too much the original result list (List<Object>) is used and the list elements are printed using the result of the ScriptEngine method toString(Object object).

In addition to the prnt command options REPL console print method has some 'hidden' options that can be used to customize object printing:

  • columnsIn, a list of map keys. These map values will be added to the table before all the other keys.
  • columnsOut, a list of map keys. These map values will not be inserted to the table.
  • highlightValue, a map<regex, function>. If command result map key matches with regex the highlight function is applied to the corresponding map value. The regex =* is processed after all the other regexes and the highlight function will be applied to all map values that have not been already highlighted.
  • mapSimilarity default value 0.8 i.e. if at least of 4 of the 5 results map keys match with reference key set the result will be printed out as a table.
  • objectToMap, a map<class, function>. Overrides the ScriptEngine toMap() method.
  • objectToString, a map<class, function>. Overrides the ScriptEngine toString() method.

Highlighting

COLORS environment variables

COLORS (HELP_COLORS, LS_COLORS and PRNT_COLORS) can be defined either in CONSOLE_OPTIONS map or as shell environment variables. COLORS environment variable will be used only in a case when the variable is not defined in CONSOLE_OPTIONS map. JLine system default will be used when COLORS variable is not defined.

COLORS environment variables are a colon separated list of key=colour pairs, where color is semicolon separated list of color codes that in its full extend is defined as style;fgcolor;bgcolor. In addition to the standard color format JLine support also nanorc extension format. The extension format will be applied only in a case when color does not conform the standard format.

HELP_COLORS keys

default = "ti=1;34:co=1:ar=3:op=33"

Key Comment
ar argument
co command
op option
ti title

LS_COLORS keys

There are two types of keys: file types and file extensions.

default = "di=1;91:ex=1;92:ln=1;96:fi="

Key Comment
di directory
ex executable
ln symbolic link
fi normal file
*.extension file extension (ex. *.jpg)

PRNT_COLORS keys

default = "th=1;34:rn=1;34:rs=,~grey15:mk=1;34:em=31:vs=32"

Key Comment
th table header
rn row numbers
rs row style
mk map keys
em error message
vs script line output when executing console script using -v option

Object printing

In addition to the PRNT_COLORS variable prnt command has two other highlight options used for object printing: highlightValue (see above) and valueStyle. Option valueStyle use Nano SyntaxHighlighter and it will be applied only to the strings that do not have spaces or are enclosed by quotes or any type of parenthesis.

In highlighting the first will be performed highlightValue option and after only if the value is not highlighted will be applied valueStyle option.

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