COMMENT ⊗   VALID 00017 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	\&{bot}, 7, 28.
C00004 00003	Angle of a curve, \see Direction.
C00006 00004	\&{cpen}, 28.
C00007 00005	\<carriage-return\>, 29--30.
C00009 00006	\&{fntmode}, 34
C00010 00007	Reverse apostrophe, 39.
C00011 00008	\&{bot}, 42
C00012 00009	{\tt)}, 45--46
C00014 00010	Plotting, 52--53
C00016 00011	BNF 58
C00017 00012	Equation, 62
C00018 00013	\&{var}, 64
C00019 00014	\&{maxht}, 66
C00020 00015	\&{chrmode}, 68--69
C00021 00016	{\tt"}, 77
C00022 00017	{\tt mathsy} font for \TEX, 98--99
C00023 ENDMK
C⊗;
\&{bot}, 7, 28.
Cartesian coordinates, 4.
Character width, 8.
Circular pen, 6.
Contents of this manual, table, 3.
Coordinates, 4.
\&{cpen}, 6.
Curved lines, 8--22.
Dangerous bend, 2.
\&{draw}, 6.
\&{draw}, 8--22.
Equations, 5--6.
Exercises, answers, 3.
Descartes, Ren\'e, 4.
Fontomania, 7.
\&{lft}, 8, 28.
METAFONT, meaning of, 4.
Pen size, 6--7.
Points, 4--5.
Raster, 1, 5.
\&{rt}, 8, 28.
Scaling, 5.
Solution of equations, 5--6.
Statements, 4.
Straight line, 6.
\&{top}, 8, 28.
Union Jack, 6.
$w$-variables, 7.
$x$-variables, 4.
$y$-variables, 4.
Angle of a curve, \see Direction.
Bean shape, 9.
Circles, 11.
Circles, 21.
Cubic spline curves, 20--22.
Direction of a curve, 10--20. Implicit, 10--13,18,20. Explicit, 13--20.
Ellipses, 12.
Ellipses, 21.
Explicit directions for a curve, 13--20.
Extreme points, 16, 19, 54
Heart shape, 12--17, 23.
Hidden points, 12; \also Invisible points.
Horizontal extrema, 16, 19, 54
Implicit directions for a curve, 10--13, 18, 20.
Inflection points, 18--19.
Invariance property of \MF\ curves, 10.
Knuth, Donald Ervin, 12.
Knuth, me, 17.
Locality property of \MF\ curves, 10.
\&{maxvr}, 22, 65
\&{maxvs}, 22, 65
\&{minvr}, 22, 65
\&{minvs}, 22, 65
Pens, 22--28.
Scaling, 10.
``{\tt Sharp turn suppressed ...}'', 21, 77.
Shoemaker's problem, 17--19.
Sole, 17--19, 23.
Velocities, 21--22, 65
Vertical extrema, 16, 19, 54
\&{cpen}, 28.
\&{cpen}, 22--23.
Discreteness, 25--27.
Elliptical pens, 22--25.
\&{epen}, 27--28.
\&{epenxcorr}, 27.
\&{epenxfactor}, 27.
\&{epenycorr}, 27.
\&{epenyfactor}, 27.
Erasers, 24, 27, appE
Eraser, 28.
Explicit pens, 27--28.
Heart and sole, 23.
$h↓0$, 22--23.
\&{hpen}, 22--23.
\&{hpen}, 28.
\&{hpenht}, 23.
\&{lpen}, 28.
\&{lpen}, 24.
Oblique pen, 25.
Pen size, 22.
Plotting points, 26--28.
\&{rpen}, 24.
\&{rpen}, 28.
\&{spen}, 24--25.
Triangular pen, 27.
$v↓0$, 22--23.
\&{vpen}, 22--23.
\&{vpen}, 28.
\&{vpenwd}, 23.
\<carriage-return\>, 29--30.
{\tt <cr>}, 30.
Davis, Chandler, 33.
{\tt DRAGON}, 33--38
Dragon curve, 33, 35.
\&{drawdisplay}, 29.
\&{end}, 33
Equations, 31--33.
Errors, 29--33, 36--38.
{\tt errors.tmp}, 33.
``{\tt ! Inconsistent equation}'', 33, 73
Knuth, me, 33.
Knuth, Jill Carter, 33.
{\tt <lf>}, 30.
``{\tt ! Missing = sign}'', 30--31, 75
{\tt mfput}, 33
\&{new}, 33
\&{proofmode}, 29, 32
Quoted strings, 34--35
``{\tt ! Redundant equation}'', 32, 76
Running \MF, 29--38.
Solution of equations, 31--33.
\&{spen}, 28.
Subscripts, 31.
\TEX, 34.
``{\tt ! Undefined factor}'', 31, 78
$w$-variables, 32
$x$-variables, 32
XGP (Xerox Graphics Printer), 33.
$y$-variables, 32
\&{fntmode}, 34
\&{tfxmode}, 34
\&{titletrace}, 34
\&{maxht}, 34
\&{charcode}, 34--35
{\tt"}, 34--35
{\≡%≡\}, 35
Comments, 35
\&{charht}, 35--36
\&{charwd}, 35--36
\&{chardp}, 35--36
\&{chardw}, 35--36
On-line error correction, 36--38
Deletion (on line), 36--37.
Insertion (on line), 37--38.
Tokens, 36--37
Text editor, 36--37
File names, 37
``{\tt ! Lookup failed}'', 37, 74
``{\tt ! Input page ended}'', 37--38, 73
\&{no}, 38
\&{pagewarning}, 38.
\&{end}, 38.
\TEX, 38
Equations, 39--46.
Variables, 39--40, 45.
Constants, 39, 45
Apostrophe, 39
{\≡≡'≡\}, 39.
{\≡≡`≡\}, 39.
Reverse apostrophe, 39.
\&{charcode}, 39
\<identifier\>, 39
$wxy$-variables, 39
$w$-variables, 39
$x$-variables, 39
$y$-variables, 39
Coordiantes, 39
Points, 39
\<index\>, 40
Spaces, 40.
Blank spaces, 40.
Period, 40.
{\tt.}, 40.
Solution of equations, 40--41.
Known variables, 41.
Unknown variables, 41.
Independent variables, 41.
Dependent variables, 41.
\&{eqtrace}, 41.
Declarative language, 41
Expressions, 42--45.
Primary expressions, 42.
\&{nrand}, 42
\&{sqrt}, 42
\&{cosd}, 42
\&{sind}, 42
\&{round}, 42
\&{good}, 42
\&{lft}, 42
\&{bot}, 42
\&{rt}, 42
\&{top}, 42
<index>, 42
Term expressions, 43
Product, 30--31, 43
Multiplication, 30--31, 43
Division, 43
Bracket notation, 43--44
Intersection of straight lines, 44
Addition, 44
Subtraction, 44
{\tt /}, 43
{\tt *}, 43
{\tt +}, 44
{\tt -}, 44
\&{new}, 44
BNF notation, 45
\<digit\>, 45
\<identifier\>, 45
\<index\>, 45
Blank space, 45
\<carriage-return\>, 45
Period, 45--46.
{\tt.}, 45--46.
Quoted strings, 45
Full stop, 46
Multiplication, 46
Parentheses, 46
{\tt(}, 45--46
{\tt)}, 45--46
\&{round}, 46
\&{sqrt}, 46
Filling in between curves, 46--51.
\&{ddraw}, 46--49, 51.
Double drawing, 46--49, 51
Heart, 47
Current pen size, 48--50
\&{spen}, 48--49
\&{epen}, 48--49
\&{cpen}, 48--50
\&{hpen}, 48--50
\&{vpen}, 48--50
\&{lpen}, 48--50
\&{rpen}, 48--50
\&{safetyfactor}, 48
\&{draw}, 49--51
Stable pen size, 50
Cubic splines 50
Transformation, 51, 64--65, 67
\&{trxx}, 51, 64--65, 67
\&{tryx}, 51, 64--65, 67
\&{trxy}, 51, 64--65, 67
\&{tryy}, 51, 64--65, 67
\&{incx}, 51, 64--65, 67
\&{incy}, 51, 64--65, 67
Scaling, 51, 64--65
Pixels (picture elements), 51
Discreteness, 51--55
Rounding, 51--55
Plotting, 52--53
\&{draw}, 52--53
Reflection symmetry, 53
Symmetry, 53
Turning points, \see Extreme points, Inflection points
Diamond rule, 52--53
\&{round}, 54
\&{lft}, 54
\&{good}, 54--55
Subroutines, 55--61
\<identifier\>, 55
Arguments, 55--56
Parameters, 55--56
\&{var}, 56, 58
\&{index}, 56, 58
\&{call}, 56--59
\&{proofmode}, 57
$x$-variables, 56--57
$y$-variables, 56--57
$w$-variables, 56--57
Variables, 56--57
Local variables, 56
Global variables, 56
Pen size, 56
Bracket notation, 56, App E
Names of points, 57--59, 61
Points, names of, 57--59, 61
Labels of points, 57--59, 61
Superellipse, 57--58
Hein, Piet, 58
BNF 58
Index arguments, 57, 59
Recursion, 59--60
Conditional statements, 59--60
\&{if}, 59--60
\&{fi}, 59
\&{else}, 59
\<relation\>, 59--60
``{\tt ! Indeterminate relation}'', 60, 73
Current pen type, 60, somewhere earlier
Current pen size, 60
\&{no}, 60
\&{penreset}, 60
Control bits, 60
Iterations, 60
\&{new}, 60
Assignment operation, 60--61
\&{proofmode}, 61
Summary of the language, 61--69
Sections of a program, 61--62
Period, 61--62
{\tt.}, 61--62
$x$-variables, 61
$y$-variables, 61
Variables, 61
Local variables, 61
Global variables, 61
Knuth, me, 61
Statements, 62--68
Null statement, 62
Equation, 62
Independent variables, 62
\&{new}, 62
Current pen type, 62
Pens, 62--63
\&{cpen}, 62
\hbox{\hash}, 62--63 (also see erasers earlier)(also stable size earlier)
\&{hpen}, 62
\&{vpen}, 62
\&{lpen}, 62
\&{rpen}, 62
\&{spen}, 62
\&{epen}, 63
Eraser, 62
\&{draw}, 63
\<path\>, 63
\&{ddraw}, 63
Stable pen size, 63
Direction ... 63
Quoted strings, 64
{\tt"}, 64
Titles (use entries for quoted strings)
\&{titletrace}, 64
\&{proofmode}, 64
\&{pagewarning}, 64
Conditional statement 64
\&{if}, 64
\&{else}, 64
\&{fi}, 64
\&{call}, 64
\&{var}, 64
\&{index}, 64
Reserved words, 39
Parameters, 64
Arguments, 64
Slanting, 65
{\≡{≡\}, somewhere
{\≡}≡\}, somewhere
{\tt[},   bracket
{\tt]},    bracket
{\tt|}, 49--50, 63
\&{charwd}, 65
\&{charht}, 65
\&{chardp}, 65
\&{charic}, 65
\&{epenxfactor}, 65
\&{epenyfactor}, 65
\TEX, 65
\&{epenxcorr}, 65
\&{epenycorr}, 65
\&{safetyfactor}, 65
\&{ddraw}, 65
\&{epen}, 65
Italic correction, 65, app E
\&{nseed}, 65
\&{hpen}, 65
\&{hpenht}, 65
\&{vpen}, 65
\&{vpenwd}, 65
\&{nrand}, 65
\&{maxht}, 66
\&{charcode}, 66
\&{chardw}, 66
\&{crsbreak}, 67
Alphatype, \see CRS
CRS (Cathode Ray Setter), 66
{\tt ETC}, 66
\&{dumplength}, 66
\&{dumpwindow}, 66
Control bits, 66--68
\&{no}, 66
\&{modtrace}, 66--67
\&{pagewarning}, 66--67
\&{penreset}, 66--67
\&{eqtrace}, 66
\&{titletrace}, 66
\&{calltrace}, 67
Tracing, 66--67
\&{drawtrace}, 67
\&{plottrace}, 67
\&{pause}, 67
\&{drawdisplay}, 67
\&{chardisplay}, 67
Datadisc (video terminal), 29, 67
\&{proofmode}, 67--69
Labels 67--68
\&{fntmode}, 68--69
XGP 68
CRS 68
\&{crsmode}, 68--69
\&{chrmode}, 68--69
\&{tfxmode}, 68--69
\TEX, 68
\&{varchar}, 68
\&{charlist}, 68
\&{texinfo}, 68
\&{lig}, 68
\&{invisible}, 68
\&{input}, 68--69
File name 69
{\tt mfput}, 69
Errors, 69--80
Tokens, 70
Insertion (on line), 70
On line ... 70
Tracing 70
\&{maxht}, 71
CRS, 71
\&{crsbreak}, 71
Coordinates, 71
\&{charlist}, 72
\&{epenxfactor}, 72
\&{epenyfactor}, 72
\&{new}, 73
\&{pagewarning}, 74
File name 74
\TEX, 73, 78
\&{modtrace}, 77, 79
Velocity, 77, 79
Quoted string, 77
{\tt"}, 77
Known variable, 79
Independent variable, 79
Dependent variable, 79
Datadisc, 80
\&{safetyfactor}, 81
\&{epen}, 81
\&{cosd}, 81
\&{sind}, 81
Computer Modern fonts, 82--94
XGP, 86
CRS, 86
\&{hpenht}, 88
\&{vpenwd}, 88
Recursion, 93
Rounding, 92--93
Subroutines, 91--94
\TEX, 95--101
\&{charwd}, 95, 100
\&{chardp}, 95
\&{charht}, 95
\&{charic}, 95
Italic correction, 95, 100
\&{chardw}, 95--96
Ligatures, 96--97
Kerning, 96--98
\&{lig}, 96--97
\&{kern}, 96--97
\&{tfxmode}, 96
\&{texinfo}, 98--100
{\tt mathsy} font for \TEX, 98--99
{\tt mathex  font for \TEX, 99--101
\&{charht}, 98, 100
\&{varchar}, 100
\&{charlist}, 100--101
Square root symbols, 101
Variable-size delimiters, 100--101
Built-up symbols, 100