implement where searches for ids/meta

* new syntax might need thinking about

R/name.R

@@ -273,6 +273,11 @@ neuprint_get_roiInfo <- function(bodyids, dataset = NULL, all_segments = FALSE,
 #'
 #' # starts with MBON
 #' neuprint_search("type:MBON.*", meta=FALSE)
+#'
+#' # full access to WHERE cypher queries over nodes (i.e. neurons) in neo4j
+#' # NB fields must be prefixed with n. to indicate that they are node properties.
+#' # note also that exists(n.somaLocation) is cypher to ensure soma==TRUE
+#' neuprint_search("where:exists(n.somaLocation) AND n.post>30000 AND NOT n.cropped")
 #' }
 #'
 #' \dontrun{
@@ -317,14 +322,22 @@ neuprint_search <- function(search, field = "name", fixed=FALSE, exact=NULL,
   if(isFALSE(fixed) && isFALSE(exact))
     warning("Ignoring exact=FALSE as regular expression searches are always exact!")
   nodetype = ifelse(all_segments,'Segment','Neuron')
-  fieldtype=neuprint_typeof(field, type = 'neo4j')
-  if(fieldtype=="STRING") {
-    search=glue('\\"{search}\\"')
-    operator=ifelse(fixed, ifelse(exact, "=", "CONTAINS"), "=~")
-  } else operator="="
+
+  if(isTRUE(tolower(field)=='where')) {
+    # this is a raw CYPHER query
+    where=search
+  } else {
+    fieldtype=neuprint_typeof(field, type = 'neo4j')
+    if(fieldtype=="STRING") {
+      search=glue('\\"{search}\\"')
+      operator=ifelse(fixed, ifelse(exact, "=", "CONTAINS"), "=~")
+    } else operator="="
+    where=glue("n.{field} {operator} {search}")
+  }
+
   cypher = glue("
                 MATCH (n:`{nodetype}`) \\
-                WHERE n.{field} {operator} {search} \\
+                WHERE {where} \\
                 RETURN n.bodyId")
   nc = neuprint_fetch_custom(cypher=cypher, conn=conn, dataset = dataset, ...)
   foundbodyids=unlist(nc$data)
@@ -351,9 +364,9 @@ neuprint_search <- function(search, field = "name", fixed=FALSE, exact=NULL,
 #' @return For \code{neuprint_ids}, a character vector of bodyids (of length 0
 #'   when there are none and \code{mustWork=FALSE}).
 #' @export
-#' @seealso \code{\link[neuprintr]{neuprint_search}}
-#' @section Query syntax: It is probably best just to look at the examples, but
-#'   the query syntax is as follows where square brackets denote optional parts:
+#' @section Standard query syntax: It is probably best just to look at the
+#'   examples, but the query syntax is as follows where square brackets denote
+#'   optional parts:
 #'
 #'   \code{[!/][<field>:]<query>}
 #'
@@ -367,6 +380,19 @@ neuprint_search <- function(search, field = "name", fixed=FALSE, exact=NULL,
 #'   Finally the query itself is a plain text (fixed) or regular expression
 #'   query.
 #'
+#'
+#' @section Extended query syntax: As a stepping stone to writing full CYPHER
+#'   queries against Neo4J you can used the special \code{where} keyword to
+#'   introduce your queries:
+#'
+#'   \code{where:<cypher query>}
+#'
+#'   e.g.
+#'
+#'   \code{"where:exists(n.somaLocation) AND n.post>30000 AND NOT n.cropped"}
+#'
+#'   Note that properties of individual nodes (i.e. neurons) must be prefixed
+#'   with \code{n.} as would be typical in a CYPHER query.
 #' @examples
 #' \donttest{
 #' # exact match against whole type

tests/testthat/test-name.R

@@ -73,6 +73,10 @@ test_that("test searches on non-string fields", {
   expect_is(neuprint_ids("cropped:false"), 'character')
 })
 
+test_that("test where searches", {
+  expect_is(neuprint_ids("where:exists(n.somaLocation) AND n.post>10000 AND NOT n.cropped"), "character")
+})
+
 test_that("test bad dataset specification ", {
   expect_error(neuprint_search(".*DA2.*", dataset = 'hemibrain1'))
 })