Valid plan rejected for no clear reason

[mabdula]

In the attached zip file there is a domain, instance and a plan that seems valid (INVAL says so), while VAL says that it is not. The only explanation I can think of is that the action defined in the domain has no preconditions.

bug3.zip

Cheers,
Mohammad

[DerekLong101]

Thanks for these. I will take a look and get back to you. Sent from Samsung tablet. -------- Original message --------From: mabdula <notifications@github.com> Date: 03/06/2018 17:27 (GMT+00:00) To: KCL-Planning/VAL <VAL@noreply.github.com> Cc: Subscribed <subscribed@noreply.github.com> Subject: [KCL-Planning/VAL] Valid plan rejected for no clear reason (#29) In the attached zip file there is a domain, instance and a plan that seems valid (INVAL says so), while VAL says that it is not. The only explanation I can think of is that the action defined in the domain has no preconditions. bug3.zip Cheers, Mohammad — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or mute the thread. {"@context":"http://schema.org","@type":"EmailMessage","potentialAction":{"@type":"ViewAction","target":"https://github.com/KCL-Planning/VAL/issues/29","url":"https://github.com/KCL-Planning/VAL/issues/29","name":"View Issue"},"description":"View this Issue on GitHub","publisher":{"@type":"Organization","name":"GitHub","url":"https://github.com"}} {"api_version":"1.0","publisher":{"api_key":"05dde50f1d1a384dd78767c55493e4bb","name":"GitHub"},"entity":{"external_key":"github/KCL-Planning/VAL","title":"KCL-Planning/VAL","subtitle":"GitHub repository","main_image_url":"https://assets-cdn.github.com/images/email/message_cards/header.png","avatar_image_url":"https://assets-cdn.github.com/images/email/message_cards/avatar.png","action":{"name":"Open in GitHub","url":"https://github.com/KCL-Planning/VAL"}},"updates":{"snippets":[{"icon":"DESCRIPTION","message":"Valid plan rejected for no clear reason (#29)"}],"action":{"name":"View Issue","url":"#29"}}} { "@type": "MessageCard", "@context": "http://schema.org/extensions", "hideOriginalBody": "false", "originator": "37567f93-e2a7-4e2a-ad37-a9160fc62647", "title": "Valid plan rejected for no clear reason (#29)", "sections": [ { "text": "", "activityTitle": "**mabdula**", "activityImage": "https://assets-cdn.github.com/images/email/message_cards/avatar.png", "activitySubtitle": "@mabdula", "facts": [ { "name": "Repository: ", "value": "KCL-Planning/VAL" }, { "name": "Issue #: ", "value": 29 } ] } ], "potentialAction": [ { "name": "Add a comment", "@type": "ActionCard", "inputs": [ { "isMultiLine": true, "@type": "TextInput", "id": "IssueComment", "isRequired": false } ], "actions": [ { "name": "Comment", "@type": "HttpPOST", "target": "https://api.github.com", "body": "{\n\"commandName\": \"IssueComment\",\n\"repositoryFullName\": \"KCL-Planning/VAL\",\n\"issueId\": 29,\n\"IssueComment\": \"{{IssueComment.value}}\"\n}" } ] }, { "name": "Close issue", "@type": "HttpPOST", "target": "https://api.github.com", "body": "{\n\"commandName\": \"IssueClose\",\n\"repositoryFullName\": \"KCL-Planning/VAL\",\n\"issueId\": 29\n}" }, { "targets": [ { "os": "default", "uri": "#29" } ], "@type": "OpenUri", "name": "View on GitHub" }, { "name": "Unsubscribe", "@type": "HttpPOST", "target": "https://api.github.com", "body": "{\n\"commandName\": \"MuteNotification\",\n\"threadId\": 341873591\n}" } ], "themeColor": "26292E" }

[DerekLong101]

This one is not very interesting, either - the precondition field is not optional so the parser fails in the action and then gets confused by the rest of the input.

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________________________________ From: mabdula <notifications@github.com> Sent: 03 June 2018 17:27:09 To: KCL-Planning/VAL Cc: Subscribed Subject: [KCL-Planning/VAL] Valid plan rejected for no clear reason (#29) In the attached zip file there is a domain, instance and a plan that seems valid (INVAL says so), while VAL says that it is not. The only explanation I can think of is that the action defined in the domain has no preconditions. bug3.zip<https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FKCL-Planning%2FVAL%2Ffiles%2F2066133%2Fbug3.zip&data=01%7C01%7Cderek.long%40kcl.ac.uk%7C6f41fad86308443dec4108d5c96edaef%7C8370cf1416f34c16b83c724071654356%7C0&sdata=TDz2%2BHxko2q0zTNrAWUA6jWILnfWA3ZVQIt4mCr5nks%3D&reserved=0> Cheers, Mohammad — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub<https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FKCL-Planning%2FVAL%2Fissues%2F29&data=01%7C01%7Cderek.long%40kcl.ac.uk%7C6f41fad86308443dec4108d5c96edaef%7C8370cf1416f34c16b83c724071654356%7C0&sdata=L8M4FJgzzD1URUVGumWtDqgBnB%2BwXt6IUk93ktmCXW0%3D&reserved=0>, or mute the thread<https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fnotifications%2Funsubscribe-auth%2FAHSnVBLN8iJxBfe0np9JyTv1lmSg3JXQks5t5A5dgaJpZM4UYJO3&data=01%7C01%7Cderek.long%40kcl.ac.uk%7C6f41fad86308443dec4108d5c96edaef%7C8370cf1416f34c16b83c724071654356%7C0&sdata=AhoNn5NIKuaGEHhNf726M4ZGoaqGDWyMzst%2FRreQaak%3D&reserved=0>.

[mabdula]

I see. Just to confirm my understanding, the syntax accepted by VAL does not conform to the BNF by Kovacs or the one in McDermot et. al's report on PDDL1.2, which both seem to suggest that the precondition field is optional. Is that correct? And if it is, is there a document summarising the syntax accepted by VAL?

Cheers
Mohammad

[DerekLong101]

Yes, quite right, VAL does not accept a missing precondition field. The rule in the parser is: c_action_def : OPEN_BRAC ACTION NAME c_args_head OPEN_BRAC c_typed_var_list CLOSE_BRAC PRE c_pre_goal_descriptor EFFECTS c_effect CLOSE_BRAC | OPEN_BRAC ACTION error CLOSE_BRAC ; Kovacs' syntax was his own effort to synthesise a grammar and postdates the construction of VAL by very many years. The PDDL syntax in the original PDDL 2.1 paper, extended to account for PDDL3.1 (constraints), PDDL2.2 (TILs, derived predicates) and TIFs (analogous to TILs, but assigning values to numeric fluents), PDDL+ (events, processes) are all handled. The PDDL2.1 paper is confusing in that it specifies fields for durative actions (conditions and effects) as required, but for actions as optional. So, this specification suggests that VAL should be permissive about preconditions. However, it is not. I think that the PDDL2.1 BNF is about as close as you will get, other than scrutiny of the pddl.yacc file. The main issues of divergence will be in the corner cases (such as you identify). Cheers Derek

…

________________________________ From: mabdula <notifications@github.com> Sent: 06 June 2018 10:41:33 To: KCL-Planning/VAL Cc: Long, Derek; Comment Subject: Re: [KCL-Planning/VAL] Valid plan rejected for no clear reason (#29) I see. Just to confirm my understanding, the syntax accepted by VAL does not conform to the BNF by Kovacs or the one in McDermot et. al's report on PDDL1.2, which both seem to suggest that the precondition field is optional. Is that correct? And if it is, is there a document summarising the syntax accepted by VAL? Cheers Mohammad — You are receiving this because you commented. Reply to this email directly, view it on GitHub<https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FKCL-Planning%2FVAL%2Fissues%2F29%23issuecomment-395009901&data=01%7C01%7Cderek.long%40kcl.ac.uk%7C2de23ef01c20436e0ea808d5cb91b21e%7C8370cf1416f34c16b83c724071654356%7C0&sdata=FMmlcNCDukYYZOoz%2FwTjFeXp6ol%2BoIgf9w6FK%2FRxlsA%3D&reserved=0>, or mute the thread<https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fnotifications%2Funsubscribe-auth%2FAHSnVAAHKU3PkqPk5G4Yf-PFPSur_XI6ks5t56PNgaJpZM4UYJO3&data=01%7C01%7Cderek.long%40kcl.ac.uk%7C2de23ef01c20436e0ea808d5cb91b21e%7C8370cf1416f34c16b83c724071654356%7C0&sdata=Xb%2BlRSjeHWxw1vQgTTc0hsWu0JOYBwjXFChTN%2FddotE%3D&reserved=0>.

[mabdula]

I see, thanks a lot for your response.

Cheers
Mohammad

[guicho271828]

@mabdula @DerekLong101 This is fixed in #25

[guicho271828]

should be closed

[DerekLong101]

As noted.