How to wrap nested string (metadata) into TagGroup - dm-script

Question

My imported metadata has a pre-defined nested structure (an example show in the following), which is a single string after imported to DM.
The whole metadata and each branch level are included in brace marks {}, all the key and key values are included by quotation marks "" and deliminated by colon :
My question is, how to convert the data and wrap them into a TagGroup object so that indexing, searching and data accessing operations can be done much easier?
Thanks!
Here is an example:
{
"Acquisition": {
"AcquisitionStartDatetime": {
"DateTime": "1473763749"
},
"AcquisitionDatetime": {
"DateTime": "0"
},
"BeamType": "",
"SourceType": "Monochromator"
},
"BinaryResult": {
"AcquisitionUnit": "",
"CompositionType": "",
"DetectorIndex": "3",
"Detector": "HAADF",
"PixelSize": {
"width": "5.408370946750477e-010",
"height": "5.408370946750477e-010"
},
"PixelUnitX": "m",
"PixelUnitY": "m",
"Offset": {
"x": "-2.769085924736244e-007",
"y": "-2.769085924736244e-007"
},
"Encoding": ""
},
"Sample": "",
"GasInjectionSystems": ""
}

Answer 1

As Mike has pointed out in the comments, this is rather a tedious than difficult task. Best to create a little parser script in a separate class which turns formats
"NAME: { into TagGroups of label NAME plus an increased hierachy level.
and
"NAME": "VALUE" into Tags of label NAME and value VALUE.
and
} into a 'reduce hierachy level' step.
Note, that you can always use String when creating the taggroup, even if you want to read it out as number at a later time point.
Recursivly browse and remember the "taggroup-level" you are in, so that each new tag is added at that level. Skip invalid text sections.
The F1 help documenation of DigitalMicrograph has a section on strings, which lists the commands you're most likely to need:
String StringAppend( String s1, String s2 )
Number StringCompare( String s1, String s2 )
Boolean StringIsValid( String str )
String StringToLower( String str )
String StringToUpper( String str )
Number len( String str )
String left( String str, Number count )
String mid( String str, Number offset, Number count )
String right( String str, Number count )
Number find( String s1, String s2 )
Number val( String str )
Additionally, I find it sometimes useful to user the tert-operator for strings like in
number isOK = 1
string str = isOK == 1 ? "true" : "false"
Also, when parsing, watch out for tabulator and line return characters. (Use \t and \n to search for them. You might need to use "\n" and "\t" when specifying int in a string, as \ will be interpreted as control character.)

Answer 2

Edit: Fixed code now
I'm sure some a more cleaned up version is possible, but it does the task:
Class CMetaStringToTagGroup
{
// Find next string bracketed by " in input string, starting search
// at given index. Returns string and end-position of search
string FindNextKeyName( object self, string input, number & searchPos )
{
number totalLength = len( input )
number start = 0, end = 0
while( searchPos < totalLength )
{
searchpos++
if ( "\"" == input.mid(searchpos-1,1) )
{
if ( !start )
start = searchpos-1
else
{
end = searchpos-1
return input.mid(start+1,end-start-1)
}
}
}
return ""
}
// Returns the next of either "{" , "}" or """ after a collon ":"
string GetNextIndicator( object self, string input, number & searchPos )
{
number totalLength = len( input )
while( searchPos < totalLength )
{
searchpos++
if ( "{" == input.mid(searchpos-1,1) )
return "{"
if ( "}" == input.mid(searchpos-1,1) )
return "}"
if ( "\"" == input.mid(searchpos-1,1) )
return "\""
}
return ""
}
// In a tag-path string, find location of last colon
number findLastColon( object self, string input )
{
number totalLength = len( input )
number lastPos = -1
number searchPos = 0
while( searchPos < totalLength )
{
searchpos++
if ( ":" == input.mid(searchpos-1,1) )
lastPos = searchpos-1
}
return lastPos
}
// Parse textstring and create taggroup from it
TagGroup CreateTagFromText( object self, string input )
{
TagGroup rootTG = NewTagGroup()
string currentPath = ""
number totalLength = len( input )
number searchPos = 0
number searchPos2
string keyName, indicator
while( searchPos < totalLength )
{
// search for new key or closing bracket, whatever first
searchPos2 = searchPos
indicator = self.GetNextIndicator( input, searchPos2 )
keyName = self.FindNextKeyName( input, searchPos )
if ( ( "}" == indicator ) && (searchpos2<searchPos ) )
{
// decrease hierachy
number cutPos = self.findLastColon( currentPath )
currentPath = left( currentPath, cutPos )
result("\n DEC ")
searchPos = searchPos2
}
else
{
// Either add value or new sub-tagGroup
if ( "" == keyname ) break; // No more keys found
indicator = self.GetNextIndicator( input, searchPos )
if ( "" == indicator ) break; // No more indicator found -- should not happen!
if ( "{" == indicator )
{
// increase hierachy
currentPath += ":" + keyname
rootTg.TagGroupSetTagAsTagGroup( currentPath, NewTagGroup() )
result("\n INC ("+keyname+")")
}
else if ( "\"" == indicator )
{
// Add value
searchPos--
string valStr = self.FindNextKeyName( input, searchPos )
rootTg.TagGroupSetTagAsString( currentPath + ":" + keyname, valStr )
result("\n VAL("+keyname+") ")
}
}
}
return rootTg
}
}
{
// Reading input text
number fileID = OpenFileForReading("C:\\test.txt")
object fStream = NewStreamFromFileReference(fileID,1)
string inputStr = fStream.StreamReadAsText(0, fStream.StreamGetSize())
// Parsing text
number searchPos = 0
TagGroup con = alloc(CMetaStringToTagGroup).CreateTagFromText( inputStr )
con.TagGroupopenBrowserwindow("",0)
}