jx_repl1

Usage

Overview

jx_repl is an interactive tool to explore the JX expression 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 JX.

•

values display a list of values supported by JX.

•

operators display a list of operators supported by JX.

•

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(out_1, type=="wq_master") 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_3 : join(project(out_2, name), ", ") out_3 : NAME_1, NAME_2, NAME_3, ..., NAME_N

Now, fetch the query used to attain that output

% jx_repl in_4 : in_4 out_4 : join(project(select(fetch("http://catalog.cse.nd.edu:9097/query.json"),type=="wq_master"),name),", ")

Call one of reserved commands

% jx_repl in_5 : 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