Promote "echo" syntax without parenthesis
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Adam Stankiewicz
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4246f660ea
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cd574d1976
7 changed files with 93 additions and 93 deletions
124
doc/tut1.txt
124
doc/tut1.txt
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@ -31,9 +31,9 @@ We start the tour with a modified "hello world" program:
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.. code-block:: Nim
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# This is a comment
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echo("What's your name? ")
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echo "What's your name? "
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var name: string = readLine(stdin)
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echo("Hi, ", name, "!")
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echo "Hi, ", name, "!"
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Save this code to the file "greetings.nim". Now compile and run it::
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@ -250,11 +250,11 @@ The if statement is one way to branch the control flow:
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.. code-block:: nim
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let name = readLine(stdin)
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if name == "":
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echo("Poor soul, you lost your name?")
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echo "Poor soul, you lost your name?"
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elif name == "name":
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echo("Very funny, your name is name.")
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echo "Very funny, your name is name."
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else:
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echo("Hi, ", name, "!")
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echo "Hi, ", name, "!"
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There can be zero or more ``elif`` parts, and the ``else`` part is optional.
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The keyword ``elif`` is short for ``else if``, and is useful to avoid
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@ -272,13 +272,13 @@ a multi-branch:
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let name = readLine(stdin)
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case name
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of "":
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echo("Poor soul, you lost your name?")
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echo "Poor soul, you lost your name?"
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of "name":
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echo("Very funny, your name is name.")
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echo "Very funny, your name is name."
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of "Dave", "Frank":
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echo("Cool name!")
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echo "Cool name!"
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else:
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echo("Hi, ", name, "!")
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echo "Hi, ", name, "!"
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As it can be seen, for an ``of`` branch a comma separated list of values is also
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allowed.
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@ -291,11 +291,11 @@ For integers or other ordinal types value ranges are also possible:
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# this statement will be explained later:
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from strutils import parseInt
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echo("A number please: ")
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echo "A number please: "
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let n = parseInt(readLine(stdin))
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case n
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of 0..2, 4..7: echo("The number is in the set: {0, 1, 2, 4, 5, 6, 7}")
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of 3, 8: echo("The number is 3 or 8")
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of 0..2, 4..7: echo "The number is in the set: {0, 1, 2, 4, 5, 6, 7}"
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of 3, 8: echo "The number is 3 or 8"
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However, the above code does not compile: the reason is that you have to cover
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every value that ``n`` may contain, but the code only handles the values
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@ -306,8 +306,8 @@ the compiler that for every other value nothing should be done:
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.. code-block:: nim
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...
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case n
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of 0..2, 4..7: echo("The number is in the set: {0, 1, 2, 4, 5, 6, 7}")
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of 3, 8: echo("The number is 3 or 8")
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of 0..2, 4..7: echo "The number is in the set: {0, 1, 2, 4, 5, 6, 7}"
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of 3, 8: echo "The number is 3 or 8"
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else: discard
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The empty `discard statement`_ is a *do nothing* statement. The compiler knows
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@ -327,10 +327,10 @@ The while statement is a simple looping construct:
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.. code-block:: nim
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echo("What's your name? ")
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echo "What's your name? "
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var name = readLine(stdin)
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while name == "":
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echo("Please tell me your name: ")
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echo "Please tell me your name: "
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name = readLine(stdin)
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# no ``var``, because we do not declare a new variable here
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@ -346,9 +346,9 @@ provides. The example uses the built-in `countup <system.html#countup>`_
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iterator:
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.. code-block:: nim
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echo("Counting to ten: ")
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echo "Counting to ten: "
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for i in countup(1, 10):
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echo($i)
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echo $i
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# --> Outputs 1 2 3 4 5 6 7 8 9 10 on different lines
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The built-in `$ <system.html#$>`_ operator turns an integer (``int``) and many
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@ -358,19 +358,19 @@ other types into a string. The variable ``i`` is implicitly declared by the
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Each value is ``echo``-ed. This code does the same:
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.. code-block:: nim
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echo("Counting to 10: ")
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echo "Counting to 10: "
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var i = 1
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while i <= 10:
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echo($i)
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echo $i
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inc(i) # increment i by 1
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# --> Outputs 1 2 3 4 5 6 7 8 9 10 on different lines
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Counting down can be achieved as easily (but is less often needed):
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.. code-block:: nim
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echo("Counting down from 10 to 1: ")
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echo "Counting down from 10 to 1: "
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for i in countdown(10, 1):
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echo($i)
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echo $i
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# --> Outputs 10 9 8 7 6 5 4 3 2 1 on different lines
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Since counting up occurs so often in programs, Nim also has a `..
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@ -390,7 +390,7 @@ outside the loop:
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.. code-block:: nim
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while false:
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var x = "hi"
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echo(x) # does not work
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echo x # does not work
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A while (for) statement introduces an implicit block. Identifiers
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are only visible within the block they have been declared. The ``block``
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@ -399,7 +399,7 @@ statement can be used to open a new block explicitly:
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.. code-block:: nim
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block myblock:
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var x = "hi"
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echo(x) # does not work either
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echo x # does not work either
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The block's *label* (``myblock`` in the example) is optional.
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@ -412,18 +412,18 @@ innermost construct, unless a label of a block is given:
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.. code-block:: nim
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block myblock:
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echo("entering block")
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echo "entering block"
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while true:
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echo("looping")
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echo "looping"
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break # leaves the loop, but not the block
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echo("still in block")
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echo "still in block"
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block myblock2:
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echo("entering block")
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echo "entering block"
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while true:
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echo("looping")
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echo "looping"
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break myblock2 # leaves the block (and the loop)
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echo("still in block")
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echo "still in block"
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Continue statement
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@ -435,7 +435,7 @@ the next iteration immediately:
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while true:
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let x = readLine(stdin)
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if x == "": continue
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echo(x)
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echo x
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When statement
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@ -446,13 +446,13 @@ Example:
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.. code-block:: nim
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when system.hostOS == "windows":
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echo("running on Windows!")
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echo "running on Windows!"
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elif system.hostOS == "linux":
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echo("running on Linux!")
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echo "running on Linux!"
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elif system.hostOS == "macosx":
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echo("running on Mac OS X!")
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echo "running on Mac OS X!"
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else:
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echo("unknown operating system")
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echo "unknown operating system"
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The ``when`` statement is almost identical to the ``if`` statement with some
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differences:
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@ -533,17 +533,17 @@ procedures are defined with the ``proc`` keyword:
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.. code-block:: nim
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proc yes(question: string): bool =
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echo(question, " (y/n)")
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echo question, " (y/n)"
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while true:
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case readLine(stdin)
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of "y", "Y", "yes", "Yes": return true
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of "n", "N", "no", "No": return false
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else: echo("Please be clear: yes or no")
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else: echo "Please be clear: yes or no"
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if yes("Should I delete all your important files?"):
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echo("I'm sorry Dave, I'm afraid I can't do that.")
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echo "I'm sorry Dave, I'm afraid I can't do that."
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else:
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echo("I think you know what the problem is just as well as I do.")
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echo "I think you know what the problem is just as well as I do."
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This example shows a procedure named ``yes`` that asks the user a ``question``
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and returns true if they answered "yes" (or something similar) and returns
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@ -611,8 +611,8 @@ caller, a ``var`` parameter can be used:
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var
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x, y: int
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divmod(8, 5, x, y) # modifies x and y
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echo(x)
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echo(y)
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echo x
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echo y
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In the example, ``res`` and ``remainder`` are `var parameters`.
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Var parameters can be modified by the procedure and the changes are
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@ -701,8 +701,8 @@ Nim provides the ability to overload procedures similar to C++:
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if x: result = "true"
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else: result = "false"
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echo(toString(13)) # calls the toString(x: int) proc
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echo(toString(true)) # calls the toString(x: bool) proc
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echo toString(13) # calls the toString(x: int) proc
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echo toString(true) # calls the toString(x: bool) proc
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(Note that ``toString`` is usually the `$ <system.html#$>`_ operator in
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Nim.) The compiler chooses the most appropriate proc for the ``toString``
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@ -743,7 +743,7 @@ The "``" notation can also be used to call an operator just like any other
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procedure:
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.. code-block:: nim
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if `==`( `+`(3, 4), 7): echo("True")
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if `==`( `+`(3, 4), 7): echo "True"
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Forward declarations
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@ -790,9 +790,9 @@ Iterators
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Let's return to the boring counting example:
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.. code-block:: nim
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echo("Counting to ten: ")
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echo "Counting to ten: "
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for i in countup(1, 10):
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echo($i)
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echo $i
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Can a `countup <system.html#countup>`_ proc be written that supports this
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loop? Lets try:
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@ -1000,15 +1000,15 @@ there is a difference between the ``$`` and ``repr`` outputs:
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myString = "nim"
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myInteger = 42
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myFloat = 3.14
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echo($myBool, ":", repr(myBool))
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echo $myBool, ":", repr(myBool)
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# --> true:true
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echo($myCharacter, ":", repr(myCharacter))
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echo $myCharacter, ":", repr(myCharacter)
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# --> n:'n'
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echo($myString, ":", repr(myString))
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echo $myString, ":", repr(myString)
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# --> nim:0x10fa8c050"nim"
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echo($myInteger, ":", repr(myInteger))
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echo $myInteger, ":", repr(myInteger)
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# --> 42:42
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echo($myFloat, ":", repr(myFloat))
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echo $myFloat, ":", repr(myFloat)
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# --> 3.1400000000000001e+00:3.1400000000000001e+00
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@ -1040,7 +1040,7 @@ at runtime by 0, the second by 1 and so on. Example:
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north, east, south, west
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var x = south # `x` is of type `Direction`; its value is `south`
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echo($x) # writes "south" to `stdout`
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echo $x # writes "south" to `stdout`
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All comparison operators can be used with enumeration types.
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@ -1133,7 +1133,7 @@ Arrays can be constructed via ``[]``:
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x: IntArray
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x = [1, 2, 3, 4, 5, 6]
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for i in low(x)..high(x):
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echo(x[i])
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echo x[i]
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The notation ``x[i]`` is used to access the i-th element of ``x``.
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Array access is always bounds checked (at compile-time or at runtime). These
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@ -1208,7 +1208,7 @@ to specify a range from zero to the specified index minus one:
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x = [1, 2, 3, 4, 5, 6]
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y = x
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for i in low(x)..high(x):
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echo(x[i], y[i])
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echo x[i], y[i]
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Sequences
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@ -1254,13 +1254,13 @@ value. Here the ``for`` statement is looping over the results from the
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.. code-block:: nim
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for i in @[3, 4, 5]:
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echo($i)
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echo $i
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# --> 3
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# --> 4
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# --> 5
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for i, value in @[3, 4, 5]:
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echo("index: ", $i, ", value:", $value)
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echo "index: ", $i, ", value:", $value
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# --> index: 0, value:3
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# --> index: 1, value:4
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# --> index: 2, value:5
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@ -1386,16 +1386,16 @@ integer.
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# the same, but less readable:
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person = ("Peter", 30)
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echo(person.name) # "Peter"
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echo(person.age) # 30
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echo person.name # "Peter"
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echo person.age # 30
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echo(person[0]) # "Peter"
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echo(person[1]) # 30
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echo person[0] # "Peter"
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echo person[1] # 30
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# You don't need to declare tuples in a separate type section.
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var building: tuple[street: string, number: int]
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building = ("Rue del Percebe", 13)
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echo(building.street)
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echo building.street
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# The following line does not compile, they are different tuples!
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#person = building
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@ -1503,7 +1503,7 @@ techniques.
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Example:
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.. code-block:: nim
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proc echoItem(x: int) = echo(x)
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proc echoItem(x: int) = echo x
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proc forEach(action: proc (x: int)) =
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const
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