| | 91 | The Heredoc processor has only one task: flattening heredoc strings. By "flattening", I mean the following. This string: |
| | 92 | |
| | 93 | {{{ |
| | 94 | $S0 = <<'EOS' |
| | 95 | This is |
| | 96 | a multi-line |
| | 97 | heredoc |
| | 98 | string |
| | 99 | with |
| | 100 | increasing |
| | 101 | indention |
| | 102 | on each line. |
| | 103 | EOS |
| | 104 | }}} |
| | 105 | |
| | 106 | is "flattened" into: |
| | 107 | |
| | 108 | {{{ |
| | 109 | $S0 = "This is a multi-line\n heredoc\n string\n with\n increasing\n indention\n on each line." |
| | 110 | }}} |
| | 111 | |
| | 112 | Note that "newline" characters are inserted as well, so that the string is equivalent to the original heredoc string. |
| | 113 | Besides assigning heredoc strings to String registers, the PIR specification also allows you to use heredoc strings as arguments in subroutine invocations: |
| | 114 | |
| | 115 | {{{ |
| | 116 | .sub main |
| | 117 | foo(<<'A') |
| | 118 | This is a heredoc |
| | 119 | string argument |
| | 120 | A |
| | 121 | .end |
| | 122 | |
| | 123 | .sub foo |
| | 124 | # ... |
| | 125 | .end |
| | 126 | }}} |
| | 127 | |
| | 128 | Again, the heredoc string (delimited by the string "A") will be flattened. According to the PIR specification, you can even pass multiple heredoc string arguments, like so: |
| | 129 | |
| | 130 | {{{ |
| | 131 | .sub main |
| | 132 | foo(<<'A', 42, <<'B', 3.14, <<'C') |
| | 133 | I have a Parrot |
| | 134 | A |
| | 135 | It is not a bird |
| | 136 | B |
| | 137 | It is a virtual machine |
| | 138 | C |
| | 139 | .end |
| | 140 | |
| | 141 | }}} |
| | 142 | |
| | 143 | Note that the heredoc arguments may be mixed with other, simple arguments such as integers and numbers. In the rest of this section, the implementation will be discussed. |
| | 144 | |
