syntax error

[Claude “Duke” Normandin]

Reading: https://programming.muthu.co/posts/beginners-guide-to-eiffel/#what-is-eiffel

`gec' chokes on the following code with:

gec person.e
Syntax error:
line 21 column 1 in person.e

The code is copied right off the above article! What's going on? TIA ...

class MAIN
^
feature

class PERSON
feature
name: STRING
age: INTEGER
set_name (new_name: STRING)
do
name := new_name
ensure
name_set: name = new_name
end
print_info
do
print ("Name: " + name + ", Age: " + age.out)
end
end
class APPLICATION
feature
main
local
p: PERSON
do
create p.set_name ("Alice")
p.age := 30
p.print_info
end
end

[Eric Bezault]

Only one class per file. The text of class PERSON goes to person.e
and the text of class APPLICATION goes to application.e.

When that done, the code will still not compile because it is not
void-safe. You will have to specify a creation procedure in class
PERSON. And you need a setter for `age`. And `main` needs to be
declared as creation procedure in APPLICATION. In the end you
should have that:

~~~~~~~
class PERSON

create

set_name

feature
name: STRING
age: INTEGER

set_name (new_name: STRING)
do
name := new_name
ensure
name_set: name = new_name
end

set_age (new_age: INTEGER)
require
new_age_not_negative: new_age >= 0
do
age := new_age
ensure
age_set: age = new_age

end

print_info
do
print ("Name: " + name + ", Age: " + age.out)
end
end

~~~~~~~
class APPLICATION

create

main

feature
main
local
p: PERSON
do
create p.set_name ("Alice")

p.set_age (30)
p.print_info
end
end

~~~~~~~

Then type: gec application.e

PS: It looks like the person who wrote this post on
https://programming.muthu.co has never programmed in
Eiffel. None of the examples will compile as is.
It might a good way to learn Eiffel though, trying to
fix the examples by understanding what the error
messages are complaining about.

--
Eric Bezault
mailto:er...@gobosoft.com
http://www.gobosoft.com


On 09/12/2025 7:20, Claude “Duke” Normandin wrote:
> Reading: https://programming.muthu.co/posts/beginners-guide-to-eiffel/
> #what-is-eiffel

>
> `gec' chokes on the following code with:
>

> *gec person.e
> Syntax error:
> line 21 column 1 in person.e*

>
> The code is copied right off the above article! What's going on? TIA ...
>

> /class MAIN
> ^
> feature/
> /class PERSON

> feature
> name: STRING
> age: INTEGER
> set_name (new_name: STRING)
> do
> name := new_name
> ensure
> name_set: name = new_name
> end
> print_info
> do
> print ("Name: " + name + ", Age: " + age.out)
> end
> end
> class APPLICATION
> feature
> main
> local
> p: PERSON
> do
> create p.set_name ("Alice")
> p.age := 30
> p.print_info
> end

> end/

[Ulrich Windl]

Hi!

Looking at the example I think it's just a complicated way to print one fixed line. The age could be a parameter of the creation procedure also.
I think the example should create at least two persons, also adding a non-trivial query, maybe "older_than(other : PERSON): BOOLEAN“. Then add some IF to the main code. Probably it will still print a constant.
The compiler I'm dreaming of would notice that, optimize the code accordingly, finally telling the user.
C compilers can do that, BTW.

Ulrich

09.12.2025 09:41:38 Eric Bezault <er...@gobosoft.com>:

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[Duke Normandin]

@Eric, @Ulrich

Thank you for both your replies.
I'm a little disappointed that I stumbled on am eiffel tutorial
that is so "out-to-lunch" to put it mildly. It's a bad way for
someone to start learning a new language.

Yes! Fixing the code will be a good exercise, but for day 2 of my
eiffel journey, fixing code would be hubris IMHO.

I need to see how a complete - but short - eiffel program is layed
out and why so.

I need to learn the syntax.

Is there a beginner's tutorial - NOT a PHD dissertation - to learn
ieffel with?

There is nothing at learnxinyminutes.com.
https://rosettacode.org/wiki/Category:Eiffel has a lot of code
snippets, but not a short, complete, not-too-trivial,
not-too-complex program.

Thanks again for all your input.
--
Duke

[Claude “Duke” Normandin]

> The compiler I'm dreaming of would notice that, optimize the code accordingly, finally telling the user.
> C compilers can do that, BTW.

Maybe C3? or Zig or Odin? I'm test-driving those as well.

[Ian Joyner]

Hello Duke,

Here are some old ones, first one I wrote maybe 20 years ago:

[Duke Normandin]

On Wed, 10 Dec 2025 10:59:36 +1100
Ian Joyner <joyne...@gmail.com> wrote:

Thank you, Ian!!

Looking forward to diving into the pdf attachments. I had a peek at
the quara posts, and as a noob to OOP as well, I'm sure that I'll
get a lot from your articles there!
--
Duke

[Ulrich Windl]

Hi!

I don't have it at hand right now, but there was Robert Switzers's book "Introduction to Eiffel" (AFAIR)
https://archive.org/details/eiffelintroducti0000swit
I have no idea how much this still represents current Eiffel, however.

Ulrich

09.12.2025 14:25:03 'Duke Normandin' via Eiffel Users <eiffel...@googlegroups.com>:

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[Ulrich Windl]

Ian,

why did you add velocity that simply returns attribute speed? I only browsed the document...

Ulrich

[rfo amalasoft.com]

Hi Duke (et al)

This might help, or perhaps not 🙂

R

---

From: 'Duke Normandin' via Eiffel Users <eiffel...@googlegroups.com>
Sent: Tuesday, December 9, 2025 7:28 PM
To: eiffel...@googlegroups.com <eiffel...@googlegroups.com>
Subject: Re: [eiffel-users] syntax error

 

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[Ian Joyner]

I can’t remember that far back. I’m sure there are things that need revision.

Ian

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[Duke Normandin]

On Wed, 10 Dec 2025 12:11:57 +0100 (GMT+01:00)
Ulrich Windl <u202...@gmail.com> wrote:

> I don't have it at hand right now, but there was Robert
> Switzers's book "Introduction to Eiffel" (AFAIR)
> https://archive.org/details/eiffelintroducti0000swit I have no
> idea how much this still represents current Eiffel, however.

Thx - but the book is "Limited View" - a lot of pages are missing -
for some reason. I've got enough to read at the moment anyway.
Thanks again ...

--
Duke

[Duke Normandin]

On Wed, 10 Dec 2025 12:12:15 +0000
rfo amalasoft.com <r...@amalasoft.com> wrote:

> This might help, or perhaps not 🙂

Thx ..
--
Duke