jx_repl

NAME

jx_repl - interactive command line tool to explore the JX language.

SYNOPSIS

jx_repl

DESCRIPTION

jx_repl is an interactive tool to explore the JX language. jx_repl will read in a JX expression, evaluate it, print the result, then save both the query and the result to the context. Results of previous expressions can be referenced via the out_%d‘ symbol, and their corresponding query via the ‘in_%d‘ symbol. The program will exit on EOF or when the user enters ’quit’ or ’exit.

jx_repl also reserves certain symbols in the context to act as commands when entered:

	•		help display a help message which lists details on reserved commands.
	•		functions display a list of functions supported by the JX language.
	•		values display a list of values supported by the JX language.
	•		operators display a list of operators supported by the JX language.
	•		catalog fetch the catalog data.
	•		exit exit the program.
	•		quit same as ’exit’.

EXIT STATUS

Will always return 0

EXAMPLES

Simply run jx_repl with no parameters:

% jx_repl

Welcome to the JX Language Explorer.

Type ’help’ for help

in_0 >>>

Enter any valid JX expression:

% jx_repl

in_0 >>> [ "file" + x + ".txt" for x in range(3) ]
out_0 <<<
[
"file0.txt",
"file1.txt",
"file2.txt"
]

Fetch the catalog data:

% jx_repl

in_1 >>> catalog
out_1 <<<
[
{
"name":NAME,
"lastheardfrom":1620308581,
"address":ADDRESS,
...
"type":"wq_factory"
},

...
]

Perform operations on previous output

% jx_repl

in_2 >>> select(type=="wq_master", out_1)
out_2 <<<
[

{
"name":NAME,
"lastheardfrom":1620308755,
"address":ADDRESS,
"tasks_total_disk":0,
"tasks_total_memory":0,
...
"type": wq_master
}
...
]

Do more operations on previous output

% jx_repl

in_4 >>> join(project(name, out_2), ", ")
out_4 <<< NAME_1, NAME_2, NAME_3, ..., NAME_N

Now, fetch the query used to attain that output

% jx_repl

in_5 >>> in_4
out_5 <<< join(project(name,select(type=="wq_master",fetch("http://catalog.cse.nd.edu:9097/query.json"))),", ")

Call one of reserved commands

% jx_repl

in_7 >>> help

help display this message
functions display a list of functions supported by the JX language
values display a list of values supported by the JX language
operators display a list of operators supported by the JX language
in_# the #’th input query
out_# result of in_#
catalog alias to fetch catalog data
quit|exit exit program

COPYRIGHT

The Cooperative Computing Tools are Copyright (C) 2005-2019 The University of Notre Dame. This software is distributed under the GNU General Public License. See the file COPYING for details.