1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 | <!doctype html> <html> <head> <title>CodeMirror: Ruby mode</title> <link rel="stylesheet" href="../../lib/codemirror.css"> <script src="../../lib/codemirror.js"></script> <script src="ruby.js"></script> <style> .CodeMirror {border-top: 1px solid black; border-bottom: 1px solid black;} .cm-s-default span.cm-arrow { color: red; } </style> <link rel="stylesheet" href="../../doc/docs.css"> </head> <body> <h1>CodeMirror: Ruby mode</h1> <form><textarea id="code" name="code"> # Code from http://sandbox.mc.edu/~bennet/ruby/code/poly_rb.html # # This program evaluates polynomials. It first asks for the coefficients # of a polynomial, which must be entered on one line, highest-order first. # It then requests values of x and will compute the value of the poly for # each x. It will repeatly ask for x values, unless you the user enters # a blank line. It that case, it will ask for another polynomial. If the # user types quit for either input, the program immediately exits. # # # Function to evaluate a polynomial at x. The polynomial is given # as a list of coefficients, from the greatest to the least. def polyval(x, coef) sum = 0 coef = coef.clone # Don't want to destroy the original while true sum += coef.shift # Add and remove the next coef break if coef.empty? # If no more, done entirely. sum *= x # This happens the right number of times. end return sum end # # Function to read a line containing a list of integers and return # them as an array of integers. If the string conversion fails, it # throws TypeError. If the input line is the word 'quit', then it # converts it to an end-of-file exception def readints(prompt) # Read a line print prompt line = readline.chomp raise EOFError.new if line == 'quit' # You can also use a real EOF. # Go through each item on the line, converting each one and adding it # to retval. retval = [ ] for str in line.split(/\s+/) if str =~ /^\-?\d+$/ retval.push(str.to_i) else raise TypeError.new end end return retval end # # Take a coeff and an exponent and return the string representation, ignoring # the sign of the coefficient. def term_to_str(coef, exp) ret = "" # Show coeff, unless it's 1 or at the right coef = coef.abs ret = coef.to_s unless coef == 1 && exp > 0 ret += "x" if exp > 0 # x if exponent not 0 ret += "^" + exp.to_s if exp > 1 # ^exponent, if > 1. return ret end # # Create a string of the polynomial in sort-of-readable form. def polystr(p) # Get the exponent of first coefficient, plus 1. exp = p.length # Assign exponents to each term, making pairs of coeff and exponent, # Then get rid of the zero terms. p = (p.map { |c| exp -= 1; [ c, exp ] }).select { |p| p[0] != 0 } # If there's nothing left, it's a zero return "0" if p.empty? # *** Now p is a non-empty list of [ coef, exponent ] pairs. *** # Convert the first term, preceded by a "-" if it's negative. result = (if p[0][0] < 0 then "-" else "" end) + term_to_str(*p[0]) # Convert the rest of the terms, in each case adding the appropriate # + or - separating them. for term in p[1...p.length] # Add the separator then the rep. of the term. result += (if term[0] < 0 then " - " else " + " end) + term_to_str(*term) end return result end # # Run until some kind of endfile. begin # Repeat until an exception or quit gets us out. while true # Read a poly until it works. An EOF will except out of the # program. print "\n" begin poly = readints("Enter a polynomial coefficients: ") rescue TypeError print "Try again.\n" retry end break if poly.empty? # Read and evaluate x values until the user types a blank line. # Again, an EOF will except out of the pgm. while true # Request an integer. print "Enter x value or blank line: " x = readline.chomp break if x == '' raise EOFError.new if x == 'quit' # If it looks bad, let's try again. if x !~ /^\-?\d+$/ print "That doesn't look like an integer. Please try again.\n" next end # Convert to an integer and print the result. x = x.to_i print "p(x) = ", polystr(poly), "\n" print "p(", x, ") = ", polyval(x, poly), "\n" end end rescue EOFError print "\n=== EOF ===\n" rescue Interrupt, SignalException print "\n=== Interrupted ===\n" else print "--- Bye ---\n" end </textarea></form> <script> var editor = CodeMirror.fromTextArea(document.getElementById("code"), { mode: "text/x-ruby", tabMode: "indent", matchBrackets: true, indentUnit: 4 }); </script> <p><strong>MIME types defined:</strong> <code>text/x-ruby</code>.</p> <p>Development of the CodeMirror Ruby mode was kindly sponsored by <a href="http://ubalo.com/">Ubalo</a>, who hold the <a href="LICENSE">license</a>.</p> </body> </html> |