diff --git a/docs/language/core.rst b/docs/language/core.rst index 42070cf..a51b488 100644 --- a/docs/language/core.rst +++ b/docs/language/core.rst @@ -862,6 +862,32 @@ Return an iterator of `x`, `fn(x)`, `fn(fn(x))`. [5, 25, 625, 390625, 152587890625] +.. _read-fn: + +read +---- + +Usage: ``(read [stdin eof])`` + +Reads the given form and parses it to hy. Takes optional argument +for a different stdin object or eof byte. Throws `EOFError` when +stdin is empty. + +.. code-block:: hy + => (read) + (+ 2 2) + ('+' 2 2) + => (eval (read)) + (+ 2 2) + 4 + => (import io) + => (def buffer (io.StringIO "(+ 2 2)\n(- 2 1)")) + => (eval (apply read [] {"stdin" buffer})) + 4 + => (eval (apply read [] {"stdin" buffer})) + 1 + + .. _remove-fn: remove diff --git a/hy/core/language.hy b/hy/core/language.hy index d7ee3ec..d6a3837 100644 --- a/hy/core/language.hy +++ b/hy/core/language.hy @@ -26,8 +26,10 @@ (import itertools) (import functools) (import collections) +(import sys) (import [hy._compat [long-type]]) ; long for python2, int for python3 (import [hy.models.cons [HyCons]]) +(import [hy.lex [LexException PrematureEndOfInput tokenize]]) (defn _numeric-check [x] @@ -326,12 +328,29 @@ (_numeric_check n) (= n 0)) +(defn read [&optional [stdin sys.stdin] + [eof ""]] + "Read from input and returns a tokenized string. + Can take a given input buffer to read from" + (def buff "") + (while true + (def inn (str (.read stdin 1))) + (if (= inn eof) + (throw (EOFError "Reached end of file" ))) + (setv buff (+ buff inn)) + (try + (def parsed (first (tokenize buff))) + (except [e [LexException PrematureEndOfInput IndexError]]) + (else (if parsed (break))))) + parsed) + + (def *exports* '[butlast calling-module-name coll? cons cons? cycle dec distinct disassemble drop drop-while empty? even? every? first filter filterfalse flatten float? gensym identity inc input instance? integer integer? integer-char? iterable? iterate iterator? keyword? list* macroexpand macroexpand-1 map neg? nil? none? nth - numeric? odd? pos? range remove repeat repeatedly + numeric? odd? pos? range read remove repeat repeatedly rest reduce second some string string? take take-nth take-while zero? zip zip_longest zipwith]) diff --git a/tests/native_tests/language.hy b/tests/native_tests/language.hy index b7888e2..9955394 100644 --- a/tests/native_tests/language.hy +++ b/tests/native_tests/language.hy @@ -1028,3 +1028,30 @@ (foo [&rest spam] 1) (catch [NameError] True) (else (raise AssertionError)))) + +(defn test-read [] + "NATIVE: test that read takes something for stdin and reads" + (if-python2 + (import [StringIO [StringIO]]) + (import [io [StringIO]])) + (import [hy.models.expression [HyExpression]]) + + (def stdin-buffer (StringIO "(+ 2 2)\n(- 2 2)")) + (assert (= (eval (apply read [] {"stdin" stdin-buffer})) 4)) + (assert (isinstance (apply read [] {"stdin" stdin-buffer}) HyExpression)) + + "Multiline test" + (def stdin-buffer (StringIO "(\n+\n41\n1\n)\n(-\n2\n1\n)")) + (assert (= (eval (apply read [] {"stdin" stdin-buffer})) 42)) + (assert (= (eval (apply read [] {"stdin" stdin-buffer})) 1)) + + "EOF test" + (def stdin-buffer (StringIO "(+ 2 2)")) + (apply read [] {"stdin" stdin-buffer}) + (try + (apply read [] {"stdin" stdin-buffer}) + (catch [e Exception] + (print e) + (assert (isinstance e EOFError))))) + +