Reading from Stdin and Writing to Stdout

Writing to Stdout

To print something on the stdout we have two options, first we can print the expression or atom as is or we can convert the expression values to ASCII characters and print them to stdout.

Examples

Here's a overly complicated Hello World program in mewl

[=mew [[+[* mewmewmew mewmew] mew] mewmew] ] //H
[=mewmew [mew [- mew mew] mew]] //e
[=mewmewmew [mew [- mew mew] [* mewmewmewmew mewmew]]] //l
[=mewmewmewmew [mew mew mew]] //o
[=mewmewmewmewmew [mewmewmew mewmew]] //SPACE
[=mewmewmewmewmewmew [[* mewmewmewmew mewmew] mewmewmewmewmewmewmew]] //W
[=mewmewmewmewmewmewmew [mew mew mewmewmewmew]] //r
[=mewmewmewmewmewmewmewmew [mew [- mew mew] [- mew mew]]] //d
[=mewmewmewmewmewmewmewmewmew [mewmewmew mewmewmew]] //!

[::: ~mew //H
~mewmew //e
~mewmewmew //l
~mewmewmew //l
~mewmewmewmew //o
~mewmewmewmewmew //SPACE 
~mewmewmewmewmewmew //W
~mewmewmewmew //o
~mewmewmewmewmewmewmew //r
~mewmewmew //l
~mewmewmewmewmewmewmewmew //d
~mewmewmewmewmewmewmewmewmew //!
]

Reading From Stdin

Read Mew/Normal Number from Stdin

Syntax of reading mew/normal number from stdin is:

[|> Variable_To_Store_Number]

Here's a simple example,

[|> =mew]
[:: ~mew]

This example, reads a number/mewnum from stdin and prints it to stdout.

• Learn about Identifiers/Assignment

Read a String from Stdin and store the length

Syntax is just like reading number from stdin,

[||> =mew]
[:: ~mew]

Just like before, read a string from stdin and print the length of the string.

Example/Usage

a. Count the character of a file using mewl

First, let's create a simple script (it is just the above example code)

[||> =mew]
[:: ~mew]

save it with filename char_len.mew.txt

Now, we need the target file, from which we will count characters from, for this example we will create a file,

$ echo "Foo bar" >foobar.txt

Now, run

$ cat foobar.txt | mewl char_len.mew.txt

If everything is right, you'll see 7 in the terminal!