From 7c3e18c7b93bf166f9a8b448e653328df898fc18 Mon Sep 17 00:00:00 2001
From: Clemens Portele <portele@interactive-instruments.de>
Date: Mon, 5 Jul 2021 14:55:10 +0200
Subject: [PATCH] BNF/JSON: update grammar (s/t/a functions, temporal literals,
 scalar with instants)

WIP: updates in text/examples/etc to follow
---
 extensions/cql/standard/schema/cql.bnf  | 48 +++++++++-----
 extensions/cql/standard/schema/cql.json | 87 +++++++++++++++----------
 2 files changed, 86 insertions(+), 49 deletions(-)

diff --git a/extensions/cql/standard/schema/cql.bnf b/extensions/cql/standard/schema/cql.bnf
index 8c180f4e..7a6a0207 100644
--- a/extensions/cql/standard/schema/cql.bnf
+++ b/extensions/cql/standard/schema/cql.bnf
@@ -52,6 +52,7 @@ binaryComparisonPredicate = scalarExpression
 scalarExpression = characterLiteral
                  | numericLiteral
                  | booleanLiteral
+                 | instantLiteral
                  | propertyName
                  | function
                  | arithmeticExpression;
@@ -91,7 +92,7 @@ isInListPredicate = inListOperand ["NOT"] "IN" leftParen inList rightParen;
 inList = inListOperand [ {comma inListOperand} ];
 
 inListOperand = scalarExpression
-              | temporalLiteral
+              | intervalLiteral
               | spatialLiteral;
 
 # IS NULL predicate
@@ -130,7 +131,8 @@ geomExpression = spatialLiteral
 # A temporal predicate evaluates if two temporal expressions satisfy the
 # specified temporal operator.
 #=============================================================================#
-temporalPredicate = temporalExpression temporalOperator temporalExpression;
+temporalPredicate = temporalOperator 
+                    leftParen temporalExpression comma temporalExpression rightParen;
 
 temporalExpression = temporalLiteral
                    | propertyName
@@ -158,7 +160,8 @@ temporalOperator = "T_AFTER"
 # not equal, less than, greater than, less than or equal, greater than or equal,
 # superset, subset and overlap operators.
 #=============================================================================#
-arrayPredicate = arrayExpression arrayOperator arrayExpression;
+arrayPredicate = arrayOperator
+                 leftParen arrayExpression comma arrayExpression rightParen;
 
 # An array expression is a bracket-delimited, comma-separated list of array
 # elements.  An array element is either a character literal, a numeric literal,
@@ -182,7 +185,7 @@ arrayElement = characterLiteral
 
 arrayOperator = "A_EQUALS"
               | "A_CONTAINS"
-              | "A_CONTAINED BY"
+              | "A_CONTAINEDBY"
               | "A_OVERLAPS";
 
 #=============================================================================#
@@ -511,18 +514,31 @@ maxElev = signedNumericLiteral;
 # NOTE: Is the fact the time zones are supported too complicated for a
 #       simple CQL? Perhaps the "core" of CQL should just support UTC.
 #=============================================================================#
-temporalLiteral = instant | interval;
-
-instant = fullDate | fullDate "T" utcTime;
-
-interval = solidus
-         | solidus dotdot
-         | dotdot solidus
-         | instant solidus
-         | solidus instant
-         | instant solidus dotdot
-         | dotdot solidus instant
-         | instant solidus instant;
+temporalLiteral = instantLiteral | intervalLiteral;
+
+instantLiteral = dateInstant | timestampInstant;
+
+dateInstant = "DATE" 
+              leftParen dateInstantString rightParen;
+
+dateInstantString = quote fullDate quote;
+
+timestampInstant = "TIMESTAMP" 
+                   leftParen timestampInstantString rightParen;
+
+timestampInstantString = quote fullDate "T" utcTime quote;
+
+instantLiteral = fullDate | fullDate "T" utcTime;
+
+intervalLiteral = "INTERVAL" 
+                  leftParen instantParameter comma instantParameter rightParen;
+
+instantParameter = instantLiteral
+                 | dateInstantString
+                 | timestampInstantString
+                 | quote dotdot quote
+                 | propertyName
+                 | function;
 
 fullDate   = dateYear "-" dateMonth "-" dateDay;
 
diff --git a/extensions/cql/standard/schema/cql.json b/extensions/cql/standard/schema/cql.json
index a6a79b98..354d8099 100644
--- a/extensions/cql/standard/schema/cql.json
+++ b/extensions/cql/standard/schema/cql.json
@@ -179,7 +179,7 @@
          "oneOf": [
             {"$ref": "#/$defs/scalarExpression"},
             {"$ref": "#/$defs/spatialLiteral"},
-            {"$ref": "#/$defs/typedTemporalLiteral"}
+            {"$ref": "#/$defs/intervalLiteral"}
          ]
       },
 
@@ -532,12 +532,12 @@
          "type": "array",
          "items": {
             "oneOf": [
-               {"$ref": "#/$defs/scalarLiteral"},
-               {"$ref": "#/$defs/spatialLiteral"},
-               {"$ref": "#/$defs/typedTemporalLiteral"},
+               { "$ref": "#/$defs/scalarLiteral"},
+               { "$ref": "#/$defs/spatialLiteral"},
+               { "$ref": "#/$defs/intervalLiteral"},
                { "$ref": "#/$defs/propertyRef" },
                { "$ref": "#/$defs/functionRef" },
-               {"$ref": "#/$defs/arithmeticExpression"},
+               { "$ref": "#/$defs/arithmeticExpression"},
                { "$ref": "#/$defs/arrayLiteral" }
             ]
          }
@@ -636,7 +636,7 @@
                   "oneOf": [
                      { "$ref": "#/$defs/scalarLiteral" },
                      { "$ref": "#/$defs/spatialLiteral" },
-                     { "$ref": "#/$defs/typedTemporalLiteral" },
+                     { "$ref": "#/$defs/intervalLiteral" },
                      { "$ref": "#/$defs/propertyRef" },
                      { "$ref": "#/$defs/functionRef" },
                      { "$ref": "#/$defs/arithmeticExpression" },
@@ -655,7 +655,8 @@
          "oneOf": [
             { "type": "string" },
             { "type": "number" },
-            { "type": "boolean"}
+            { "type": "boolean"},
+            { "$ref": "#/$defs/instantLiteral" }
          ]
       },
 
@@ -885,54 +886,74 @@
 
       "temporalLiteral": {
          "oneOf": [
-            { "$ref": "#/$defs/instantString" },
-            { "$ref": "#/$defs/intervalString" }
+            { "$ref": "#/$defs/instantLiteral" },
+            { "$ref": "#/$defs/intervalLiteral" }
          ]
       },
 
-      "instantString": {
+      "instantLiteral": {
          "oneOf": [
-            { "type": "string", "format": "date" },
-            { "type": "string", "format": "date-time" }
+            { "$ref": "#/$defs/dateLiteral" },
+            { "$ref": "#/$defs/timestampLiteral" }
          ]
       },
 
-      "intervalString": {
-         "type": "array",
-         "minItems": 2,
-         "maxItems": 2,
-         "items": {
-            "oneOf": [
-               { "$ref": "#/$defs/instantString" },
-               { "type": "string", "enum": [".."] }
-            ]
+      "dateLiteral": {
+         "type": "object",
+         "required": ["date"],
+         "properties": {
+            "date": {
+               "$ref": "#/$defs/dateString"
+            }
+         }
+      },
+
+      "timestampLiteral": {
+         "type": "object",
+         "required": ["timestamp"],
+         "properties": {
+            "timestamp": {
+               "$ref": "#/$defs/timestampString"
+            }
          }
       },
 
-      "typedTemporalLiteral": {
+      "instantString": {
          "oneOf": [
-            { "$ref": "#/$defs/typedInstantString" },
-            { "$ref": "#/$defs/typedIntervalString" }
+            { "$ref": "#/$defs/dateString" },
+            { "$ref": "#/$defs/timestampString" }
          ]
       },
 
-      "typedInstantString": {
+      "dateString": { 
+         "type": "string", 
+         "format": "date" 
+      },
+
+      "timestampString": { 
+         "type": "string", 
+         "format": "date-time"
+      },
+
+      "intervalLiteral": {
          "type": "object",
          "required": ["datetime"],
          "properties": {
             "datetime": {
-               "$ref": "#/$defs/instantString"
+               "$ref": "#/$defs/intervalArray"
             }
          }
       },
 
-      "typedIntervalString": {
-         "type": "object",
-         "required": ["datetime"],
-         "properties": {
-            "datetime": {
-               "$ref": "#/$defs/intervalString"
-            }
+      "intervalArray": {
+         "type": "array",
+         "minItems": 2,
+         "maxItems": 2,
+         "items": {
+            "oneOf": [
+               { "$ref": "#/$defs/instantString" },
+               { "type": "string", "enum": [".."] }
+            ]
          }
       }
    }