Support invoking actions directly in Ballerina shell

[nipunayf]

Purpose

Since Ballerina does not allow actions to be invoked at the module level, the current implementation has the limitation of invoking an action. As a workaround, this PR wraps the action in a function and returns the value to the module-level declared variable.

Fixes #39960
Fixes #39893

Approach

The new implementation wraps the action inside a function and returns the value to a module-level variable. Considering the user's input http:Response response = check clientEndpoint->get("/entries");, the shell generates the following snippet as a workaround for the issue.

function () returns error|http:Response __shell_wrapper__0 = function() returns error|http:Response {
    http:Response response = check clientEndpoint->get("/entries");
    return response;
};
http:Response response = check __shell_wrapper__0();

Samples

The following types of actions are now supported in Ballerina shell with this PR.

$= string returnValue = myClient->invoke("input");

$= string returnValue = myClient ->/root/name("input");

$= future<int> futureResult = start name();

Remarks

Still, the user cannot assign the output of an action to a var variable. This requires additional implementation since we have to intact the semantic model to determine the return type of the action and then generate the custom function.

Additionally, since the shell generates a function for each action, those function names are now disallowed for the user.

Check List

• Read the Contributing Guide
• Updated Change Log
• Checked Tooling Support (#)
• Added necessary tests
  • Unit Tests
  • Spec Conformance Tests
  • Integration Tests
  • Ballerina By Example Tests
• Increased Test Coverage
• Added necessary documentation
  • API documentation
  • Module documentation in Module.md files
  • Ballerina By Examples

[codecov]

Codecov Report

Attention: Patch coverage is 67.85714% with 9 lines in your changes are missing coverage. Please review.

Project coverage is 76.67%. Comparing base (991f718) to head (71349f5).
Report is 20 commits behind head on master.

Files	Patch %	Lines
...ina/shell/snippet/factory/BasicSnippetFactory.java	70.83%	3 Missing and 4 partials ⚠️
...ava/io/ballerina/shell/parser/ParserConstants.java	0.00%	0 Missing and 1 partial ⚠️
...va/io/ballerina/shell/parser/SerialTreeParser.java	50.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             master   #41587       +/-   ##
=============================================
+ Coverage      0.00%   76.67%   +76.67%     
- Complexity        0    53101    +53101     
=============================================
  Files             9     2884     +2875     
  Lines            35   200222   +200187     
  Branches          0    26081    +26081     
=============================================
+ Hits              0   153529   +153529     
- Misses           35    38260    +38225     
- Partials          0     8433     +8433     

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[github-actions]

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[github-actions]

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[github-actions]

This PR has been open for more than 15 days with no activity. This will be closed in 3 days unless the stale label is removed or commented.

[github-actions]

This PR has been open for more than 15 days with no activity. This will be closed in 3 days unless the stale label is removed or commented.

[github-actions]

This PR has been open for more than 15 days with no activity. This will be closed in 3 days unless the stale label is removed or commented.

[lochana-chathura]

LGTM. Added a few minor suggestions.