Add pragma accessors

This library requires a forked macros module, so export accessors
that would prevent a downstream library from having the same
problems with std/macros.

src/preserves.nim

@@ -635,6 +635,18 @@ template preservesRecord*(label: string) {.pragma.}
   ## Serialize this object or tuple as a record.
   ## See ``toPreserve``.
 
+proc hasPreservesRecordPragma*(T: typedesc): bool =
+  ## Test if a type has a `{.preservesRecord: "…".}` pragma attached.
+  hasCustomPragma(T, preservesRecord)
+
+proc recordLabel*(T: typedesc): string =
+  ## Get the record label set by a pragma on a type.
+  runnableExamples:
+    type Foo {.preservesRecord: "bar".} = object
+      n: int
+    assert recordLabel(Foo) == "bar"
+  T.getCustomPragmaVal(preservesRecord)
+
 template preservesTuple*() {.pragma.}
   ## Serialize this object or tuple as a tuple.
   ## See ``toPreserve``.
@@ -643,10 +655,18 @@ template preservesTupleTail*() {.pragma.}
   ## Serialize this object field to the end of its containing tuple.
   ## See ``toPreserve``.
 
+proc hasPreservesTuplePragma*(T: typedesc): bool =
+  ## Test if a type has a `preservesTuple` pragma attached.
+  hasCustomPragma(T, preservesTuple)
+
 template preservesDictionary*() {.pragma.}
   ## Serialize this object or tuple as a dictionary.
   ## See ``toPreserve``.
 
+proc hasPreservesDictionaryPragma*(T: typedesc): bool =
+  ## Test if a type has a `preservesDictionary` pragma attached.
+  hasCustomPragma(T, preservesDictionary)
+
 template preservesOr*() {.pragma.}
   ## Serialize this object as an ``or`` alternative.
   ## See ``toPreserve``.
@@ -785,6 +805,10 @@ proc fromPreserve*[T, E](v: var T; pr: Preserve[E]): bool =
     assert(fromPreserve(foo, parsePreserves("""<foo 1 2>""")))
     assert(foo.x == 1)
     assert(foo.y == 2)
+  when T is E:
+    if not pr.embedded and pr.kind == pkEmbedded:
+      v = pr.embed
+      return true
   when T is Preserve[E]:
     v = pr
     result = true

src/preserves/preserves_schema_nim.nim

@@ -10,7 +10,7 @@ import std/[hashes, sequtils, strutils, sets, tables]
 
 import compiler/[ast, idents, renderer, lineinfos]
 
-import ../preserves, ./schema, ./parse
+import ../preserves, ./schema
 
 type
   Bundle = schema.Bundle[void]
@@ -487,8 +487,7 @@ proc addFields(recList: PNode; scm: Schema; known: var TypeTable; cp: CompoundPa
 proc addFields(recList: PNode; scm: Schema; known: var TypeTable; pat: Pattern; parentName: string): PNode {.discardable.} =
   case pat.orKind
   of PatternKind.SimplePattern:
-    raiseAssert "addFields called with SimplePattern " #& $pat.simplePattern
-    # addField(recList, scm, known, pat.simplePattern, "data")
+    addField(recList, scm, known, pat.simplePattern, "data")
   of PatternKind.CompoundPattern:
     discard addFields(recList, scm, known, pat.compoundPattern, parentName)
   reclist

src/preserves/schemaparse.nim

@@ -6,7 +6,7 @@ from std/os import absolutePath, isAbsolute, getCurrentDir, parentDir
 
 import npeg
 
-import ../preserves, ./schema, ./parse, ./pegs
+import ../preserves, ./schema, ./pegs
 
 type
   Value = Preserve[void]