This is an old revision of the document!
====== Lynus Vaz: Enhanced scripting language ====== ===== Notes ===== I've taken a few ideas from Fabrice Bellard's C OTCC compiler: http://bellard.org/otcc/ Also looking at [[http://www.gnu.org/software/bash/bash.html|bash]] Here's the POSIX specification for the shell: [[http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html]] Proposed syntax: LINES => LINE '\n' LINES | e LINE => WORD | WORD WS ARG_LIST | e ARG_LIST => ARG WS ARG_LIST | e ARG => WORD SP => ' ' | '\t' WS => SP | SP WS NOT_EXP => (any - { SP, '$(', ')', '${', '}') /* Represents characters not expanded */ WORD => NOT_EXP WORD | EXP WORD | NOT_EXP | EXP EXP => EXPR_EXP | VAR_EXP /* Expansions */ EXPR_EXP => '$(' EXPR ')' VAR_EXP => '${' (any - { '}' })+ '}' EXPR => TERM | TERM BIN_OP EXPR | MONO_OP EXPR TERM => VAR_EXP | STRING NUM => ('+' | '-' )? ( '(' EXPR ')' | (digit)+ ) STRING => (any - { '$(', ')', '${', '}', ' ', BIN_OP, MONO_OP})+ /* This will help with string comparison */ BIN_OP => '*' | '/' | '%' /* Convert both operands to integers */ | '+' | '-' | '<<' | '>>' | '<' | '<=' | '>' | '>=' | '!=' | '==' /* Should also work for strings */ | '&' | '|' | '^' | '&&' | '||' MONO_OP => '~' | '!' Syntax for if-else branches: if <condition> <statements> [ else <statements> ] fi Proposed syntax for while loops: while <condition> <statements> wend Proposed syntax for for loops: for <variable> in <value list> <statements> next
