After installing Reynir, fire up your Python 3 interpreter:

$ python3

…and try something like the following:

from reynir import Reynir

my_text = "Litla gula hænan fann fræ. Það var hveitifræ."

# Initialize Reynir and submit the text as a parse job
r = Reynir()
job = r.submit(my_text)

# Iterate through sentences and parse each one
for sent in job:
    print("Sentence: {0}".format(sent.tidy_text))
    print("Lemmas:   {0}".format(sent.lemmas))
    print("Parse tree:\n{0}\n".format(sent.tree.view))

The output of the program is as follows:

Sentence: Litla gula hænan fann fræ.
Lemmas:   ['lítill', 'gulur', 'hæna', 'finna', 'fræ', '.']
Parse tree:
      +-lo_nf_et_kvk: 'Litla'
      +-lo_nf_et_kvk: 'gula'
      +-no_et_nf_kvk: 'hænan'
      +-so_1_þf_et_p3: 'fann'
        +-no_et_þf_hk: 'fræ'
Sentence: Það var hveitifræ.
Lemmas:   ['það', 'vera', 'hveitifræ', '.']
Parse tree:
      +-pfn_hk_et_nf: 'Það'
      +-so_1_nf_et_p3: 'var'
        +-no_et_nf_hk: 'hveitifræ'

The code first creates an instance of the Reynir class and assigns it to the r object. The Reynir class is Reynir’s main service interface.

Next, the program submits a piece of text containing two sentences to Reynir, which returns a job object. Each job object encapsulates a stream of sentences that will be, or have been, processed through Reynir’s tokenizer and parser.

A job object is a Python generator, and the for loop iterates through the job’s sentence stream, returning each sentence in turn in the sent object.

The for loop body parses the sentence by calling sent.parse(). This function returns True if the sentence was successfully parsed, i.e. at least one valid parse tree was found for it, or False otherwise.

The sentence object has a number of properties, including sent.tidy_text which returns a normalized form of the tokenized sentence.

If the sentence was successfully parsed, the sent.tree property (of type SimpleTree) contains its best parse tree. This tree can be further queried via properties such as sent.lemmas which returns a list of the word lemmas in the sentence, and sent.tree.view which returns a string with an “ASCII art” representation of the parse tree.

The parse tree contains grammar nonterminals in uppercase, such as P (paragraph), S-MAIN (main sentence), IP (inflected phrase - beygingarliður), NP-SUBJ (noun phrase - subject, frumlag), VP (verb phrase - sagnliður), etc.

Nonterminals are listed and explained in the Nonterminals section.

The tree also shows grammar terminals (leaves, corresponding to tokens) in lowercase, as well as their grammatical variants (features). Examples are pfn_hk_et_nf (personal pronoun, neutral gender, singular, nominative case), and so_1_nf_et_p3 (verb, one argument in nominative case, singular, 3rd person).

Terminals and variants are listed and explained in the Terminals section.

The sentence and tree properties and functions are further detailed and described in the Reference section.