doc syntax

2022-03-11 12:39:52 +01:00
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+# PL/XML Syntax
+
+Programs that do not respect this syntax may (and probably
+will) still work, but with no guarantee.
+
+## McKeeman Form
+
+```
+plxml
+    program
+
+program
+    "<program=" tag ">" functions main functions "</program>"
+
+tag
+    '"' characters '"'
+
+characters
+    ''
+    character characters
+
+character
+    '0020' . '10FFFF' - '"' - '0027' - '<' - '>' - '&'
+    '&' escapes ';'
+
+ws
+    ""
+    '0020' ws
+    '000A' ws
+    '000D' ws
+    '0009' ws
+
+escapes
+    "quot"
+    "apos"
+    "lt"
+    "gt"
+    "amp"
+
+main
+    ws "<main>" instructions "</main>" ws
+
+functions
+    ""
+    function functions
+
+function
+    ws "<function name=" tag ">" ws "<arguments>" arguments "</arguments>" ws "<body>" instructions "</body>" ws "</function>" ws
+
+arguments
+    ""
+    argument arguments
+
+argument
+    ws "<argument name=" tag "/>" ws
+
+instructions
+    ws "" ws
+    instruction instructions
+
+instruction
+    ws _instruction ws
+
+_instruction
+    value
+    assign
+    integer
+    float
+    string
+    array
+    add
+    subtract
+    multiply
+    divide
+    and
+    or
+    not
+    equal
+    greater
+    lower
+    call
+    return
+    if
+    for
+    each
+    while
+
+value
+    "<value variable=" tag "/>"
+
+assign
+    "<assign variable=" tag ">" instruction "</assign>"
+
+integer
+    "<integer value=" tag "/>"
+    "<integer>" instruction "</integer>"
+
+float
+    "<float value=" tag "/>"
+    "<float>" instruction "</float>"
+
+string
+    "<string value=" tag "/>"
+    "<string>" instruction "</string>"
+
+array
+    "<array>" instructions "</array>"
+
+add
+    "<add>" instructions "</add>"
+
+subtract
+    "<subtract>" instructions "</subtract>"
+
+multiply
+    "<multiply>" instructions "</multiply>"
+
+divide
+    "<divide>" instructions "</divide>"
+
+and
+    "<and>" instructions "</and>"
+
+or
+    "<or>" instructions "</or>"
+
+not
+    "<not>" instruction "</not>"
+
+equal
+    "<equal>" instruction instruction "</equal>"
+
+greater
+    "<greater>" instruction instruction "</greater>"
+
+lower
+    "<lower>" instruction instruction "</lower>"
+
+call
+    "<call function=" tag ">" ws "<arguments>" instructions "</arguments>" ws "</call>"
+    "<call>" instruction "<arguments>" instructions "</arguments>" ws "</call>"
+
+return
+    "<return>" instruction "</return>"
+
+if
+    "<if>" ws instruction ws "<then>" instructions "</then>" ws "</if>"
+    "<if>" ws instruction ws "<then>" instructions "</then>" ws "<else>" instructions "</else>" ws "</if>"
+
+each
+    "<each variable=" tag ">" instruction do "</each>"
+
+while
+    "<while>" instruction do "</while>"
+
+for
+    "<for variable=" tag ">" ws from to step do "</for>"
+
+from
+    ws "<from>" instruction "</from>" ws
+
+to
+    ws "<to>" instruction "</to>" ws
+
+step
+    ws "<step>" instruction "</step>" ws
+
+do
+    ws "<do>" instructions "</do>" ws
+```