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Exercise 1.17 should have the alternative statement as a + times(a, b - 1) right? Since, the question states we assume there is no * operator in the language for this question:

x => x + 4
↑ ↑ ↑ ↑ ↑
// the function with argument x that results in the value plus 4

Put the arrows like ^ inside of the program, as in a previous snippet

In the XML, the tag SCHEMEINLINE is used as synonym for JAVASCRIPTINLINE.

Currently, the tag SCHEMEINLINE seems to be ignored. Can we treat it exactly like JAVASCRIPTINLINE?

Currently, it's not:

The XML in section 1.2.6

            The 
            <SPLITINLINE>
              <SCHEME>
                <SCHEMEINLINE>smallest-divisor</SCHEMEINLINE> 
              </SCHEME>
              <JAVASCRIPT>
                <JAVASCRIPTINLINE>smallest_divisor</JAVASCRIPTINLINE> 
              </JAVASCRIPT>
            </SPLITINLINE>
            <SPLITINLINE><SCHEME>procedure</SCHEME><JAVASCRIPT>function</JAVASCRIPT></SPLITINLINE> 
            shown

is currently rendered as follows:

There is no space between smallest_divisor and "shown", although there is a newline between the two occurrences of SPLITINLINE.

Not sure if it's worth playing with tools like Inkscape to include SVG files in the LaTeX sources. Perhaps we should convert them to PNG, to keep the whole system simple.

Any views appreciated.

2.3.1, Exercise 2.53
cannot handle [], afai see.

Issue

Figures 3.29 and 3.30 in Chapter 3.4.1 The Nature of Time in Concurrent Systems are really huge. Once Chapter 3.4.1 is loaded to the screen, these figures require excessive horizontal scrolling. Even when fully zoomed out and on full screen, figure 3.29 still does not fit on screen and figure 3.30 barely fits.

Screenshots

These screenshots show fully zoomed-out browsers.
Firefox:

Chrome:

Browser versions

Mozilla Firefox 67.0.4
Google Chrome 75.0.3770

Sometimes the numbers are underlined, sometimes not, see here:

e.g starts from 1.0.1 instead of 1.1.1

There are some functions in the textbook undefined in Source Academy platform:
Chapter1:

1. In 1.1.8, function math_log, math_exp undefined;
2. In 1.2.6, a) function math_random, math_floor undefined;
   b) Library Math undefined;
3. In 1.3.3, function math_sin, math_cos undefined;

Chapter2:

1. In 2.2.4, function make_painter_from_url undefined;
2. In 2.3.3, a) In first is_element_set program, function is_equal undefined;
   b) In Exercise 2.62, function quotient undefined;
   c) In look_up program, function is_equal and key undefined
3. In 2.3.4, function symbol_leaf undefined；
4. In 2.4.3, function get undefined;
5. In 2.5.2, function put, put_coercion, get_coercion undefined;

The option <SNIPPET HIDE="yes"> is currently ignored. This leads to many extra program snippets appearing in the text, for example:

The infinite scrolling for JavaScript Adaptation Making-of does not end. Rather, it keeps rendering copies of Preface of JavaScript Adaptation.

Tested on

• Chrome 66 for Mac and
• Chrome 67.0.3396.87 (Official Build) (64-bit) for debian

The link "1.2.6" appears in the footnote part of the page for no apparent reason.

See:

For example

should be

Lamé's Theorem

The full list of special characters is in

sicp/rails/app/controllers/chapters_controller.rb:

        replace_tag(xml_doc, 'APOS', '\'')
        replace_tag(xml_doc, 'SPACE', ' ')
        replace_tag(xml_doc, 'WJ', '⁠')
        replace_tag(xml_doc, 'AACUTE_LOWER', 'á')
        replace_tag(xml_doc, 'AACUTE_UPPER', 'Á')
        replace_tag(xml_doc, 'AGRAVE_LOWER', 'à')
        replace_tag(xml_doc, 'AGRAVE_UPPER', 'À')
        replace_tag(xml_doc, 'ACIRC_LOWER', 'â')
        replace_tag(xml_doc, 'EACUTE_LOWER', 'é')
        replace_tag(xml_doc, 'EACUTE_UPPER', 'É')
        replace_tag(xml_doc, 'EGRAVE_LOWER', 'è')
        replace_tag(xml_doc, 'EGRAVE_UPPER', 'È')
        replace_tag(xml_doc, 'ECIRC_LOWER', 'ê')
        replace_tag(xml_doc, 'OUML_LOWER', 'ö')
        replace_tag(xml_doc, 'OUML_UPPER', 'Ö')
        replace_tag(xml_doc, 'UUML_LOWER', 'ü')
        replace_tag(xml_doc, 'UUML_UPPER', 'Ü')
        replace_tag(xml_doc, 'CCEDIL_LOWER', 'ç')
        replace_tag(xml_doc, 'ELLIPSIS', '…')
        replace_tag(xml_doc, 'AMP', '&')
        replace_tag(xml_doc, 'SECT', '§')
        replace_tag(xml_doc, 'EMDASH', '—')
        replace_tag(xml_doc, 'ENDASH', '–')

The subsection number in the header in this screenshot should be 1.2.2, and not 1.2.3:

That para should say "state names" instead of "program names". This is a mistake already in the original textbook.

Can be fixed by moving \label tags to be before \pagestyle tags

Exercises are currently formatted like this:

A couple of suggestions:

(1) Spacing

In the original textbook, exercises look like this:

I think this spacing is nicer: "Exercise" flushed left and no vertical space between "Exercise" and the text.

(2) Link to solution

I find the text "Link to solution" at the top a bit clumsy. How about just letting the users click on "Exercise 1.7" instead?

Would that be too obscure?

Alternatively, we could provide a link at the bottom:

We need to find a way to have reasonable sizes for the images. Do they have a "natural" size that we can use for all versions of the textbook?

Currently, the PDF version stretches images to fill the entire width of the text:

This site says they should work from iOS 11.3 onwards:
https://medium.com/@firt/progressive-web-apps-on-ios-are-here-d00430dee3a7

In chapter 3.5.2, add_stream function is defined as follows:

function add_streams(s1, s2) {
    return stream_map(function(x, y) { return x + y;},  s1, s2);
}

however, in chapter 3.5.1, steam_map takes 2 arguments only.

function stream_map(f, s) {
    if (is_empty_list(s)) {
        return [];
    } else {
        return pair(f(head(s)),
                    function() {
                        return stream_map(f, stream_tail(s));
                    });
    } 
}

solution uses 1 and 0 instead of true and false

see https://www.comp.nus.edu.sg/~cs1101s/sicp/chapters/9

Between "Source" and "1", there should be a section sign: §

This is in Preface.

Add comma: More precisely, the number of multiplications required is equal to 1 less than the log base 2 of n**,** plus the number of ones in the binary representation of n.

Shouldn't the answer for Exercise 1.15 question 2 be in terms of a and not n, i.e. it should be O(log3(a))?
The ans says it is O(log3(n)) for both time and space

In chapter 1.2.5, Exercise 1.20 solution needs to be rewritten to JavaScript as there is only scheme version.

There should be no space between the word or sentence to which a footnote refers, and the number. Currently we have:

The index of the original textbook has a nice preface. Can we have that too?

Ordered lists <OL> in exercises should lead to a display as follows:

a. Here is the first part.
b. And here is the second part.

Currently, the list is numbered numerically:

1. Here is the first part.
2. And here is the second part.

We should allow a mechanism to include names in the index. One way could be:
<INDEX>flatmap@<JAVASCRIPTINLINE>flatmap</JAVASCRIPTINLINE></INDEX>
Similarly, subindices could include names:
<INDEX>half-interval method<SUBINDEX>half@<JAVASCRIPTINLINE>half_interval_method</JAVASCRIPTINLINE></SUBINDEX></INDEX>
Neither of these currently work. I'm open to a different format or HTML tag for including names in the index and subindices.

The ^ character is an escape character in the listings package. This leads to a formating problem in section 1.1.4:

There seems to be some extra space between the number of a heading and its text. This becomes apparent if the text does not fit into one line. Example:

The original textbook has a list of exercises:

Can we have that too?

There is a change in specification for shared playground links, in the new version of source-academy at cadet-frontend.

Shared playground links must take the form,

{host}/playground#chap={chap}&ext={ext}&prgrm={lzStr}

Where

• {host} is the host of source-academy, e.g. http://stg-cadet-frontend.s3-website-ap-southeast-1.amazonaws.com for the staging server, or https://http://sourceacademy.nus.edu.sg for deployment. Required.
• {chap} is an integer representing the source chapter version. e.g. 1 for Source §1, 2 for Source §2, ... Optional, defaults to the latest chapter if missing or invalid.
• {ext} is a string representing the name of the external library to be used. The list of permitted external library names are here. For example, one can specify CURVES to allow usage of the curves library in the playground upon loading the program, ... Optional, defaults to "NONE" if missing or invalid.
• {prgrm} is a string representing the hashed program in the editor. Alternatively, the key for this parameter can also be lz, i.e. &lz={lzStr}, for back-compatibility. Required.

The order of the parameters after the hash (#) does not matter.

Examples of Valid URLs

http://stg-cadet-frontend.s3-website-ap-southeast-1.amazonaws.com/playground#chap=2&prgrm=EQQ2G4g
http://stg-cadet-frontend.s3-website-ap-southeast-1.amazonaws.com/playground#chap=2&lz=EQQ2G4g

http://stg-cadet-frontend.s3-website-ap-southeast-1.amazonaws.com/playground#chap=1&prgrm=EQQ2G4g
http://stg-cadet-frontend.s3-website-ap-southeast-1.amazonaws.com/playground#chap=2&prgrm=EQQ2G4g
http://stg-cadet-frontend.s3-website-ap-southeast-1.amazonaws.com/playground#prgrm=EQQ2G4g

http://stg-cadet-frontend.s3-website-ap-southeast-1.amazonaws.com/playground#chap=2&ext=TWO_DIM_RUNES&prgrm=EQQ2G4g
http://stg-cadet-frontend.s3-website-ap-southeast-1.amazonaws.com/playground#ext=THREE_DIM_RUNES&prgrm=EQQ2G4g

Suggestions

We use the lz-string javascript library to hash the programs into the prgrm/lz parameter value. It is probably possible to dynamically generate and parse an example program in the textbook into this hashed string, then interpolate it as a valid URL, saving a bunch of manual work (if this is not already implemented).

The tag <EMDASH/> is apparently not implemented. It should lead to an em dash. In LaTeX, an em dash is produced with three hyphens: ---

Example:

Example:

The link goes to chapter 1 instead of chapter 2.

https://www.comp.nus.edu.sg/~cs1101s/sicp/chapters/24

In typesetting, it is considered bad style to have a newline between parts that are intimately related. For example, in the sentence "The distance was 11 km as the crow flies.", there should be no newline between "11" and "km". Here is an example of this in the PDF:

There should be no newline between "section" and "1.2.1". In the XML sources, we use the tag <SPACE/> to indicate a non-breaking space:
in section<SPACE/><REF NAME="sec:recursion-and-iteration"/> the number

In LaTeX, the symbol ~ allows to place a space between two parts of a sentence, while making sure that they are never separated by a newline. So instead of
described in section \ref{sec:recursion-and-iteration} the number
we should write:
described in section~\ref{sec:recursion-and-iteration} the number
To make the long story short: We should translate <SPACE/> to ~ in LaTeX.

If there are multiple footnotes with the same number on the screen, the clicking of a footnote leads to the first footnote with that number, not necessarily the correct one.

Somehow, the listings package is not properly configured. Currently JavaScript keywords are not highlighted:

Can we turn programs in the PDF version into clickable links, similar to programs in the web version?

Issue

When scrolling down the Acknowledgements section, it jumps straight to the References section.

Expected behaviour

In the table of contents, Acknowledgements is followed by Chapter 1. As a user, this makes me expect to be led to Chapter 1 as I finish the Acknowledgements section, instead of being led to the References section.

Additional remarks

I am not sure if this is an intended behaviour. The link to Acknowledgements is suffixed with /87 (https://sicp.comp.nus.edu.sg/chapters/87), while References is suffixed with /88. With respect to this, the behaviour is not surprising. However, it could be confusing to users because of the inconsistency with the table of contents.