baum: 6279e5b14d9e baum.1

baum

view baum.1 @ 55:6279e5b14d9e

added error handling for fopen and malloc; code cleanups

author	meillo@marmaro.de
date	Sun, 16 Mar 2008 10:40:53 +0100
parents	201b4603671a
children	b7544f23673b

line source

1 .TH baum 1 "2008-03-01" "baum 0.4"

2 .SH NAME

3 baum \- an esoteric programming language

7 .SH SYNOPSIS

8 .B baum

9 [\-v]\ <file>

13 .SH DESCRIPTION

14 .B baum

15 is an interpreter for the baum programming language which is an experiment to create an esoteric programming language.

17 Source code is a representation of a tree in which every node is a command or data.

19 baum is only an experiment and the functionality is (currently) very restricted.

24 .SH OPTIONS

26 .TP

27 .BI \-v

28 Verbose output (All verbose output goes to stderr)

30 .TP

31 .BI \-\-help

32 Print usage information

34 .TP

35 .BI \-\-version

36 Print version information

43 .SH CONCEPT

45 baum programs are represented as nodes in a tree structure. Nodes are of specific kind and contain a value.

47 The tree is processed recursive starting at the root node. Every node controls it's sons and should only know them; while most nodes only use their leftmost son.

49 Each node returns a value to it's parent. (The root node returns an exit code to the shell.) The internal value of the node could be used in any useful way, but only inside the node.

51 All values in the language (return values, expected return values and in-node values) should be of the same type, so that every combination of nodes is possible.

53 Nodes can modify the tree, but should do this only on it's brothers or better only through it's rightmost brother.

57 .SH SOURCE CODE

59 Source code are plain text files with one node per line representing the tree. The indention controls in which level in the tree the node is. Indention can be made with SPACE or with TAB characters. Every character means one level.

61 Empty lines and everything vom the hash symbol (`#') to the end of the line is ignored.

63 .B An example that echoes (and returns) `42':

65 .nf

66 # comment

67 print(0)

68 sum(0) #comment

69 number(40)

70 number(2)

71 .fi

74 .SH NODES

76 .TP

77 .B create

78 Creates a new number node as last brother. The value of the new node is ether read from standard input (if the node has no son), or the return value of the first son. Returns 0 always.

80 .TP

81 .B if

82 Compares return value of first son and second son. The internal value defines how the comparation is done. 33 (`!') means not equal; 60 (`<') less than; 62 (`>') greater than; and everything else stands for equal. Requires two sons. Returns 1 for true and 0 for false.

84 .TP

85 .B number

86 Executes it's leftmost son. Returns the internal value.

88 .TP

89 .B print

90 Prints the return value of it's leftmost son. Ether as char (if the internal value is 99), or as number otherwise. Returns the return value of the leftmost son (passes through).

92 .TP

93 .B sum

94 Executes all of it's sons. Returns the sum of their return values.

96 .TP

97 .B times

98 Copies everything below the node and pastes it as last brother(s). Returns 0 always.

100 .TP

101 .B while

102 Executes it's second son as long the first son returns a logical true (not `0'). Requires two sons. Returns 0 always;

103

104

105

106

107

108

109

110 .SH ERRORS

111

112 You have to keep in mind, that valid programs that run successful can return exit codes different from zero too! Each program returns the return value of the root node to the shell. If you don't want your program doing this, just set a `number(0)' node as root, and put everything else below.

113

114 .TP

115 .BI 1

116 common error

117

118 .TP

119 .BI 3

120 no or more than one source file given

121

122 .TP

123 .BI 4

124 invalid node